Who can go Back to Godhead and who Does not Go Back to Godhead?

SB 4.12.36

The self-effulgent Vaikuṇṭha planets, by whose illumination alone all the illuminating planets within this material world give off reflected light, cannot be reached by those who are not merciful to other living entities. Only persons who constantly engage in welfare activities for other living entities can reach the Vaikuṇṭha planets.

SB 4.12.37

Persons who are peaceful, equipoised, cleansed and purified, and who know the art of pleasing all other living entities, keep friendship only with devotees of the Lord; they alone can very easily achieve the perfection of going back home, back to Godhead.

Vaishnava Dealings: How to never be affected by the three fold miseries of the world

When Narada Muni sees Dhruva feeling insulted by the sharp words of his step mother, he instructs him in the aspect of tolerance and relationships in the following way:

1. SB 4.8.28: My dear Dhruva, if you feel that your sense of honor has been insulted, you still have no cause for dissatisfaction. This kind of dissatisfaction is another feature of the illusory energy; every living entity is controlled by his previous actions, and therefore there are different varieties of life for enjoying or suffering.
1. Purport 4.8.28: Nārada Ṛṣi first of all wanted to impress upon Dhruva Mahārāja that he was only a child; he should not have been affected by words of insult or honor. And if he were so developed as to understand honor and insult, then this understanding should have been applied in his own life. He should have known that honor and dishonor are both destined only by one’s previous actions; therefore one should not be sorry or happy under any circumstances.
2. Purport 4.8.27: Ordinarily if a child is rebuked as a rascal or fool, he smiles and does not take such insulting words very seriously. Similarly, if words of honor are offered, he does not appreciate them. But in the case of Dhruva Mahārāja, the kṣatriyaspirit was so strong that he could not tolerate a slight insult from his stepmother which injured his kṣatriya prestige.
2. Purport 4.8.29 Essence: 
1.  Everyone who is intelligent should know that because of our concept of bodily existence, we are subjected to suffering and enjoyment. One who is in the transcendental position, beyond the concept of bodily life, is considered to be intelligent.
3. SB 4.8.33: "One should try to keep himself satisfied in any condition of life — whether distress or happiness — which is offered by the supreme will. A person who endures in this way is able to cross over the darkness of nescience very easily."
1. Purport 4.8.33: Instead of being attached to the circumstantial happiness and distress resulting from pious or impious activities, if we want to get out of the clutches of this nescience, then whatever position we are put in by the will of the Lord we should accept. Thus if we simply surrender unto the Supreme Personality of Godhead, we shall get out of the clutches of this material existence.
4. SB 4.8.34: Every man should act like this: when he meets a person more qualified than himself, he should be very pleased; when he meets someone less qualified than himself, he should be compassionate toward him; and when he meets someone equal to himself, he should make friendship with him. In this way one is never affected by the threefold miseries of this material world.
1. Purport: Generally when we find someone more qualified than
   
   ourselves, we become envious of him; when we find someone less qualified, we deride him; and when we find someone equal we become very proud of our activities. These are the causes of all material tribulations. 
2. The great sage Nārada therefore advised that a devotee should act perfectly. Instead of being envious of a more qualified man, one should be jolly to receive him.
3.  Instead of being oppressive to a less qualified man, one should be compassionate toward him just to raise him to the proper standard.
4.  And when one meets an equal, instead of being proud of one’s own activities before him, one should treat him as a friend. 
5. One should also have compassion for the people in general, who are suffering due to forgetfulness of Kṛṣṇa. These important functions will make one happy within this material world.

Learn to be sober and well behaved towards the Vaishnavas

From Srila Prabhupada's purport to SB 8.5.15-16
It is described that while Durvāsā Muni was passing on the road, he saw Indra on the back of his elephant and was pleased to offer Indra a garland from his own neck. Indra, however, being too puffed up, took the garland, and without respect for Durvāsā Muni, he placed it on the trunk of his carrier elephant. The elephant, being an animal, could not understand the value of the garland, and thus the elephant threw the garland between its legs and smashed it. Seeing this insulting behavior, Durvāsā Muni immediately cursed Indra to be poverty-stricken, bereft of all material opulence. Thus the demigods, afflicted on one side by the fighting demons and on the other by the curse of Durvāsā Muni, lost all the material opulences in the three worlds.

To be extremely opulent in materialistic advancement is sometimes very risky.

The materially opulent person does not care about anyone, and thus he commits offenses to great personalities, such as devotees and great saints. This is the way of material opulence. As described by Śukadeva Gosvāmī, dhana-durmadāndha: too much wealth makes one blind. This happens even to Indra in his heavenly kingdom, and what to speak of others in this material world? When one is materially opulent, he should learn to be sober and well-behaved toward Vaiṣṇavas and saintly persons; otherwise he will fall down.

1.2.18 The Two Bhagavats that help a devotee overcome that which is troublesome

What occurs after we become eager to hear, which begins the clearing of material desires from the heart?

naṣṭa-prāyeṣv abhadreṣu

nityaḿ bhāgavata-sevayā

bhagavaty uttama-śloke

bhaktir bhavati naiṣṭhikī

By regular attendance in classes on the Bhāgavatam and by rendering of service to the pure devotee, all that is troublesome to the heart is almost completely destroyed, and loving service unto the Personality of Godhead, who is praised with transcendental songs, is established as an irrevocable fact.

Important Points

A fixed mind can focus

1. In 1.2.17 the anarthas that cause unsteadiness start getting cleared by the Lord's mercy owing to the devotee's increased urge to hear. In 1.2.18 the anarthas that cause unsteadiness are almost completely destroyed . Thus the mind is fixed and can focus. This is the stage of Nistha - almost anartha nivritti. 
2. Main Point: The impediments to bhakti can be removed by service to devotees(person Bhagavata) and Bhagavatam. Thus by hearing and doing service. 
1. The messages of the book Bhagavata have to be received from the devotee Bhagavata, and the combination of these two Bhagavatas will help the neophyte devotee to make progress on and on . (From Unveiling His Lotus Feet - Page 58)
3. Importance of Relationships with devotees(mentioned by Hg Radha Krishna Prabhu while explaining this verse)
1. We avoid association of devotees because we do not want to give up material nature
1. It is impossible to do pure devotional service in association of material nature(therefore do yukta vairagya)
2. Association is important because we hear from the devotees and thus unwanted things leave our heart. Also Krishna is present in their heart.
3. On our own it is hard to grow therefore we must help each other.
4. Good relationships encourages us in service
4. From anartha nivritti you must come to nishtha else something is wrong with your execution.- Hg Radha Krishna Prabhu

1.2.16 How to get affinity for hearing the Lord's message?

śuśrūṣoḥ śraddadhānasya

vāsudeva-kathā-ruciḥ

syān mahat-sevayā viprāḥ

puṇya-tīrtha-niṣevaṇāt

SB 1.2.16: O twice-born sages, by serving those devotees who are completely freed from all vice, great service is done. By such service, one gains affinity for hearing the messages of Vāsudeva.

Some important points from Srila Prabhupada's purport

1.  The servants of God come to propagate God consciousness, and intelligent people should cooperate with them in every respect.
2. By serving the servant of God, one can please God more than by directly serving the Lord. The Lord is more pleased when He sees that His servants are properly respected because such servants risk everything for the service of the Lord and so are very dear to the Lord.
3. By serving the servants of the Lord, one gradually gets the quality of such servants, and thus one becomes qualified to hear the glories of God. The eagerness to hear about God is the first qualification of a devotee eligible for entering the kingdom of God. 

HG Radha Krishna Prabhu also mentioned in his class that we not only get affinity to hear the messages of Vasudeva but we also get the strength to act on what we have heard.

From Sivarama Swami's book "Suddha Bhakti Cintamani" Chapter entitled Eligibility for Devotion One", Pg 85:

"Rendering service to liberated devotees gives neopyhtes the strength to resist their lower conditioned nature and to stick to the higher, pure ideal of pleasing the Lord. Devotees who neglcet to keep the company with superior Vaishnavas , however, are unable to control their lower nature, and their impure faith leads them away from the path of pure devotion to the path of semblance of devotion. In this regard Caitanya Mahaprabhu quotes the following verse to Sanatana Goswami:

SB 5.12.12: My dear King Rahūgaṇa, unless one has the opportunity to smear his entire body with the dust of the lotus feet of great devotees, one cannot realize the Absolute Truth. One cannot realize the Absolute Truth simply by observing celibacy [brahmacarya], strictly following the rules and regulations of householder life, leaving home as a vānaprastha, accepting sannyāsa, or undergoing severe penances in winter by keeping oneself submerged in water or surrounding oneself in summer by fire and the scorching heat of the sun. There are many other processes to understand the Absolute Truth, but the Absolute Truth is only revealed to one who has attained the mercy of a great devotee.

Glories of a saintly person

Said by Lord Krsna to Akrura when He visits Akrura's home


SB 10.48.31: 
No one can deny that there are holy places with sacred rivers, or that the demigods appear in deity forms made of earth and stone. But these purify the soul only after a long time, whereas saintly persons purify just by being seen.

Devotees are special - The Lord is purchased by His devotees

In the pastime of Maharaj Ambarisha and Durvasa Muni - Durvasa Muni gets angry on Maharaj ambarisha for taking water to break his fast before offering Durvasa Muni any prasad to eat. He creates fiery demon to mill Ambarish Maharaj. However Ambarish Maharaj being an unalloyed devotee of the Lord does not get distrubed by the demon and the Lord's Sudarshana Chakra kills the fiery demon and then attacks Durvasa Muni.

To protect himself, Durvasa Muni starts running with the Sudarshan Chakra following him. He goes to Lord BRahma and Lord Shiva for protection but they say that they are also completely dependent upon Lord Vishnu and cannot do anything to stop the attack of the Sudarshan Chakra on him and they ask him to go to Lord Vishnu.

Lord Vishnu also says that he cannot help him as nothing in the world is greater to Him than his devotee.In the verses SB 9.4.63-9.4.71 Lord Vishnu speaks very highly of the surrendered devotees and also about His love for them. Since the devotees are so selflessly engaged in loving service to the Lord , the Lord is purchased by them and offers complete protection to them. Since Durvasa Muni acted out of consideration for himself and pride the Lord did not offer him the same level of protection as He offers to Ambarisha Maharaj

1. I am under the control of My devotees SB 9.4.63  the Lord says :"I am completely under the control of My devotees. Indeed, I am not at all independent. Because My devotees are completely devoid of material desires, I sit only within the cores of their hearts. What to speak of My devotee, even those who are devotees of My devotee are very dear to Me." - the Lord indicates to Durvasa Muni that Ambarisha Maharaj is a devotee and one who becomes a devotee of a devotee is also very special to him- the right thing for Durvasa Muni to do would be to honor and respect Ambarish Maharaj. Also Srila Prabhupada says in the purport "** if one very sincerely serves the spiritual master, Kṛṣṇa certainly becomes favorable to such a devotee. Following the instructions of a devotee is more valuable than following the instructions of the Supreme Personality of Godhead directly." So we must first learn to surrender to devotees if we can do that then we can surrender to the Spiritual Master and then Krishna.
2. I wish to be surrounded by saintly persons always SB 9.4.64 : "O best of the brāhmaṇas, without saintly persons for whom I am the only destination, I do not desire to enjoy My transcendental bliss and My supreme opulences." Krishna is so personal!
3. Since they are selflessly working for My pleasure- I must be with them SB 9.4.65: "Since pure devotees give up their homes, wives, children, relatives, riches and even their lives simply to serve Me, without any desire for material improvement in this life or in the next, how can I give up such devotees at any time?" The Lord gives all protection to the devotees because they are trying to serve Him incessantly.How can the Lord then not give Ambarisa Maharaj protection?
4. I am in control of My devotees SB 9.4.66 : "As chaste women bring their gentle husbands under control by service, the pure devotees, who are equal to everyone and completely attached to Me in the core of the heart, bring Me under their full control."
5. Do not hurt My devotees - it pains Me :SB 9.4.68: "The pure devotee is always within the core of My heart, and I am always in the heart of the pure devotee. My devotees do not know anything else but Me, and I do not know anyone else but them." - Srila Prabhupada says " The Lord's feelings are like those of a father, who feels pain when his child is in pain. Therefore, offenses at the lotus feet of a devotee are serious. Caitanya Mahāprabhu has very strongly recommended that one not commit any offense at the lotus feet of a devotee. "
6. I will forgive you, if you ask for forgiveness from Ambarisa Maharaj SB 9.4.69 : "O brāhmaṇa, let Me now advise you for your own protection. Please hear from Me. By offending Mahārāja Ambarīṣa, you have acted with self-envy. Therefore you should go to him immediately, without a moment's delay. One's so-called prowess, when employed against the devotee, certainly harms he who employs it. Thus it is the subject, not the object, who is harmed." Srila Prabhupada writes in the purport :"harmful activities directed against the devotee gradually become the ultimate cause of the performer's falldown. Even such a great brāhmaṇa and mystic yogī as Durvāsā was in a most dangerous situation because of his offense at the lotus feet of Mahārāja Ambarīṣa, a pure devotee"

Sacrificial fire and brahamanas are considered to be the mouth of Vishnu

SB 8.16.9:
By worshiping the fire and the brāhmaṇas, a householder can achieve the desired goal of residing in the higher planets, for the sacrificial fire and the brāhmaṇas are to be considered the mouth of Lord Viṣṇu, who is the Supersoul of all the demigods

From Srila Prabhupada's purport:
"If one offers Me with love and devotion a leaf, a flower, fruit or water, I will accept it." Therefore, all these items may be offered in the sacrificial fire, and Lord Viṣṇu will be satisfied. Similarly, brāhmaṇa-bhojana, feeding of the brāhmaṇas, is also recommended, for when the brāhmaṇas eat sumptuous remnants of food after yajña, this is another way that Lord Viṣṇu Himself eats. Therefore the Vedic principles recommend that in every festival or ceremony one offer oblations to the fire and give sumptuous food for the brāhmaṇas to eat. By such activities, a householder may be elevated to the heavenly planets and similar places in the higher planetary systems.


SB 5.5.23
O respectful brāhmaṇas, as far as I am concerned, no one is equal or superior to the brāhmaṇas in this world. I do not find anyone comparable to them. When people know My motive, after performing rituals according to the Vedic principles they offer food to Me with faith and love through the mouth of a brāhmaṇa. When food is thus offered unto Me, I eat it with full satisfaction. Indeed, I derive more pleasure from food offered in that way than from the food offered in the sacrificial fire.

One must carry out the order of the Spiritual master and serve the brahamanas nicely

In the sixth canto after Indra offends his Guru Brhaspati , the demigods were being rapidly defeated by the demons who took advantage of their weak condition.Being thus bewidered and weakened the demigoids approached Lord Brahma for help.

On looking at their pitiable condition Lord Brahma said :

SB 6.7.22: Because of your misbehavior toward Bṛhaspati, you have been defeated by the demons. My dear demigods, since the demons were weak, having been defeated by you several times, how else could you, who were so advanced in opulence, be defeated by them?

All the opulence we possess is thus a result of the blessings of Guru and the Guru Parampara. By ourselves without the mercy of the Spiritual Master and the Guru Paramapara we are insignificant. Any of our endeavors is successful only because if the mercy and the backing of the entire Guru Parampara.

Prior to devotional life every endeavor of mine was plagued with many hurdles and resulted in miniscule success. However in devotional life anything done under the direction of authority is always successful. Pleasing our authorities means we follow their directions properly.When we do so we are able to recieve their blessings and mercy to complete the endeavor.

However if we offend our authority we will find ourselves completely weakened like the demigods.The mercy will be withdrawn automatically.

Further in the 8th canto,in the fight between the demons and the demigods after the nectar from the churning of the milk ocean is consumed by the demigods, Bali was defeated, and he died in the fight, but by the grace of Śukrācārya he regained his life. Thus he engaged himself in the service of Śukrācārya, his spiritual master.
The descendants of Bhṛgu, being pleased with him, engaged him in the Viśvajit-yajña. When this yajña was performed, from the fire of yajña came a chariot, horses, a flag, a bow, armor and two quivers of arrows. Mahārāja Prahlāda, Bali Mahārāja's grandfather, gave Bali an eternal garland of flowers, and Śukrācārya gave him a conchshell. Bali Mahārāja, after offering obeisances to Prahlāda, the brāhmaṇas and his spiritual master, Śukrācārya, equipped himself to fight with Indra and went to Indrapurī with his soldiers.Blowing his conchshell, he attacked the outskirts of Indra's kingdom. When Indra saw Bali Mahārāja's prowess, he went to his own spiritual master, Bṛhaspati, told him about Bali's strength, and inquired about his duty. Bṛhaspati informed the demigods that because Bali had been endowed with extraordinary power by the brāhmaṇas, the demigods could not fight with him. Bali was endowed with the blessings of the descendents of Bhrgupati, the blessings of his spritual master Sukracarya because he had pleased him and also his forefathers.

Agaian we see that by the mercy of the spiritual master and the brahamanas Bali Maharaj becomes very powerful.
Srila Prabhupada writes in this regard in 8.15.28:
We sing in our daily prayers, yasya prasādād bhagavat-prasādo yasyāprasādān na gatiḥ kuto 'pi **. By the pleasure of the spiritual master, one can get extraordinary power, especially in spiritual advancement. The blessings of the spiritual master are more powerful than one's personal endeavor for such advancement. Narottama dāsa Ṭhākura therefore says:


guru-mukha-padma-vākya, cittete kariyā aikya,āra nā kariha mane āśā **

Especially for spiritual advancement, one should carry out the bona fide order of the spiritual master. By the paramparā system, one can thus be endowed with the original spiritual power coming from the Supreme Personality of Godhead (evaḿ paramparā-prāptam imaḿ rājarṣayo viduḥ [Bg. 4.2]).

Lord is more pleased with offerings to brahmanas than oblations to Him through the fire

SB 7.14.17: The Supreme Personality of Godhead, Śrī Kṛṣṇa, is the enjoyer of sacrificial offerings. Yet although His Lordship eats the oblations offered in the fire, my dear King, He is still more satisfied when nice food made of grains and ghee is offered to Him through the mouths of qualified brāhmaṇas.

SB 4.21.41: Although the Supreme Personality of Godhead, Ananta, eats through the fire sacrifices offered in the names of the different demigods, He does not take as much pleasure in eating through fire as He does in accepting offerings through the mouths of learned sages and devotees, for then He does not leave the association of devotees.

SB 8.16.9:
By worshiping the fire and the brāhmaṇas, a householder can achieve the desired goal of residing in the higher planets, for the sacrificial fire and the brāhmaṇas are to be considered the mouth of Lord Viṣṇu, who is the Supersoul of all the demigods

SB 5.5.23
O respectful brāhmaṇas, as far as I am concerned, no one is equal or superior to the brāhmaṇas in this world. I do not find anyone comparable to them. When people know My motive, after performing rituals according to the Vedic principles they offer food to Me with faith and love through the mouth of a brāhmaṇa. When food is thus offered unto Me, I eat it with full satisfaction. Indeed, I derive more pleasure from food offered in that way than from the food offered in the sacrificial fire.

Serving Vaishnavas gives freedom from material contamination

SB 7.5.32
Unless they smear upon their bodies the dust of the lotus feet of a Vaiṣṇava completely freed from material contamination, persons very much inclined toward materialistic life cannot be attached to the lotus feet of the Lord, who is glorified for His uncommon activities. Only by becoming Kṛṣṇa conscious and taking shelter at the lotus feet of the Lord in this way can one be freed from material contamination.

Desire to serve Vaishnavas should be stronger than a materialist's desire to enjoy Sense gratification

SB 4.22.3: Seeing the four Kumāras, Pṛthu Mahārāja was greatly anxious to receive them. Therefore the King, with all his officers, very hastily got up, as anxiously as a conditioned soul whose senses are immediately attracted by the modes of material nature.

Transcendental benefit of serving Vaishnavas

After getting blessings from Lord Vishnu, Prthu Maharaj instructed his citizens after performing another yagna. He instructed them on various aspects like following varnashrama duies,etc and also speficially talked about respecting and serving the brahamans and the vaishnavas.

The following verses spoken by him are wonderful in how they inspire one to serve the brahamana and the vaishnavas and also set the expectation that the Supreme Lord has from us.
Synopsis:

1. The Supreme Lord Himself engages in the service of brahamanas and vaishnavas
2. The Lord is pleased if we engage in their service as He is dear to them and they are dear to Him.
3. Be regular service one's heart becomes cleaned and one can get liberation from material attachment and still be very blissful and satisfied.
4. One is relieved from sinful reactions
5. One develops all good and desirable qualities.
   
6. It is more superior that any fruitive activity.
7. It is pleasing to the demigods who one tries to please by performing sacrifices
   

SB 4.21.39: The Supreme Personality of Godhead, who is everlastingly independent and who exists in everyone's heart, is very pleased with those who follow in His footsteps and engage without reservation in the service of the descendants of brāhmaṇas and Vaiṣṇavas, for He is always dear to brāhmaṇas and Vaiṣṇavas and they are always dear to Him.

SB 4.21.40: By regular service to the brāhmaṇas and Vaiṣṇavas, one can clear the dirt from his heart and thus enjoy supreme peace and liberation from material attachment and be satisfied. In this world there is no fruitive activity superior to serving the brāhmaṇa class, for this can bring pleasure to the demigods, for whom the many sacrifices are recommended.

SB 4.21.41: Although the Supreme Personality of Godhead, Ananta, eats through the fire sacrifices offered in the names of the different demigods, He does not take as much pleasure in eating through fire as He does in accepting offerings through the mouths of learned sages and devotees, for then He does not leave the association of devotees.

SB 4.21.42: In brahminical culture a brāhmaṇa's transcendental position is eternally maintained because the injunctions of the Vedas are accepted with faith, austerity, scriptural conclusions, full sense and mind control, and meditation. In this way the real goal of life is illuminated, just as one's face is fully reflected in a clear mirror.

SB 4.21.43: O respectable personalities present here, I beg the blessings of all of you that I may perpetually carry on my crown the dust of the lotus feet of such brāhmaṇas and Vaiṣṇavas until the end of my life. He who can carry such dust on his head is very soon relieved of all the reactions which arise from sinful life, and eventually he develops all good and desirable qualities.

SB 4.21.44: Whoever acquires the brahminical qualifications — whose only wealth is good behavior, who is grateful and who takes shelter of experienced persons — gets all the opulence of the world. I therefore wish that the Supreme Personality of Godhead and His associates be pleased with the brāhmaṇa class, with the cows and with me.