A devotee is always free from all bad association. Sometimes one is praised and sometimes one is defamed; that is the nature of human society. But a devotee is always transcendental to artificial fame and infamy, distress or happiness. He is very patient. He does not speak of anything but the topics about Kṛṣṇa; therefore he is called silent. Silent does not mean that one should not speak; silent means that one should not speak nonsense. One should speak only of essentials, and the most essential speech for the devotee is to speak for the sake of the Supreme Lord. A devotee is happy in all conditions; sometimes he may get very palatable foodstuffs, sometimes not, but he is satisfied. Nor does he care for any residential facility. He may sometimes live underneath a tree, and he may sometimes live in a very palatial building; he is attracted to neither. He is called fixed because he is fixed in his determination and knowledge.
(Bhagavad-Gita-----12:18-19-----purport).

In this age, men are victims not only of different political creeds and parties, but also of many different types of sense-gratificatory diversions, such as cinemas, sports, gambling, clubs, mundane libraries, bad association, smoking, drinking, cheating, pilfering, bickerings, and so on. Their minds are always disturbed and full of anxieties due to so many different engagements. In this age, many unscrupulous men manufacture their own religious faiths which are not based on any revealed scriptures, and very often people who are addicted to sense gratification are attracted by such institutions.
(Srimad Bhagavatam-----1:1:10-----translation).

In this age, people are indulging in such necessities of life without following the rules and regulations, and this deterioration of social and moral rules is certainly lamentable because of the harmful effects of such beastly behavior. In this age, the fathers and the guardians are not happy with the behavior of their wards. They should know that so many innocent children are victims of bad association awarded by the influence of this age of Kali. We know from Śrīmad-Bhāgavatam that Ajāmila, an innocent son of a brāhmaṇa, was walking down a road and saw a śūdra pair sexually embracing. This attracted the boy, and later on the boy became a victim of all debaucheries. From a pure brāhmaṇa, he fell down to the position of a wretched urchin, and it was all due to bad association. There was but one victim like Ajāmila in those days, but in this age of Kali the poor innocent students are daily victims of cinemas which attract men only for sex indulgence.
(Srimad Bhagavatam-----1:16:22-----translation).

So even though the Lord is equally well-wishing to everyone, the unfortunate living being, due to bad association only, is unable to accept His instructions in toto, and for this the Lord is never to be blamed. He is called the well-wisher for the devotees only. He appears to be partial to His devotees, but factually the matter rests on the living being to accept or reject equal treatment by the Lord.
(Srimad Bhagavatam-----1:16:26-30-----purport).

One should not, however, become self-complacent simply by leaving home or by creating another home at the holy place, either lawfully or unlawfully. Many persons leave home and go to such holy places, but due to bad association, again become family men by illicit connection with the opposite sex. The illusory energy of matter is so strong that one is apt to be under such illusion at every stage of life, even after quitting one's happy home.
(Srimad Bhagavatam-----2:1:16-----purport).

If one is in good association he can develop the mode of goodness, and if in bad association he may develop the mode of darkness or ignorance. Nothing is stereotyped. One can change his habit by good or bad association, and one has to become intelligent enough to discriminate between good and bad. The best association is the service of the devotees of the Lord, and by that association one can become the highest qualified man by the grace of the Lord's pure devotees.
(Srimad Bhagavatam-----2:10:41-----purport).

It is said that giving good counsel to a foolish person causes the fool to become angry, just as feeding milk to a snake only increases its venomous poison. Saint Vidura was so honorable that his character was looked up to by all respectable persons. But Duryodhana was so foolish that he dared to insult Vidura. This was due to his bad association with Śakuni, his maternal uncle, as well as with his friend Karṇa, who always encouraged Duryodhana in his nefarious acts.
(Srimad Bhagavatam-----3:1:14-----purport).

It is said in other purāṇas that Narakāsura was the son of Dharitrī, the earth, by the Lord Himself. But he became a demon due to the bad association of Bāṇa, another demon. An atheist is called a demon, and it is a fact that even a person born of good parents can turn into a demon by bad association. Birth is not always the criterion of goodness; unless and until one is trained in the culture of good association, one cannot become good.
(Srimad Bhagavatam-----3:3:6-----purport).

The Supreme Lord is always a well-wisher, just like a father or mother. Despite all the offenses of a son, the father and mother are always the son's well-wisher. Similarly, despite all our offenses and defiance of the desires of the Supreme Personality of Godhead, the Lord will give us immediate relief from all the hardships offered by material nature if we simply surrender unto Him, as confirmed in Bhagavad-gītā (mām eva ye prapadyante māyām etāṁ taranti te (B.G.7:14). Unfortunately, due to our bad association and great attachment for sense gratification, we do not remember our best friend, the Supreme Personality of Godhead.
(Srimad Bhagavatam-----4:28:25-----purport).

Remaining in that āśrama, the great King Bharata Mahārāja was now very careful not to fall victim to bad association. Without disclosing his past to anyone, he remained in that āśrama and ate dry leaves only. He was not exactly alone, for he had the association of the Supersoul. In this way he waited for death in the body of a deer. Bathing in that holy place, he finally gave up that body.
(Srimad Bhagavatam-----5;8;31-----purport).

Due to his being especially gifted with the Lord's mercy, Bharata Mahārāja could remember the incidents of his past life. Although he received the body of a brāhmaṇa, he was still very much afraid of his relatives and friends who were not devotees. He was always very cautious of such association because he feared that he would again fall down. Consequently he manifested himself before the public eye as a madman—dull, blind and deaf—so that others would not try to talk to him. In this way he saved himself from bad association. Within he was always thinking of the lotus feet of the Lord and chanting the Lord's glories, which save one from the bondage of fruitive action. In this way he saved himself from the onslaught of nondevotee associates.
(Srimad Bhagavatam-----5:9:3-----purport).

Jaḍa Bharata also told about his own previous birth and informed the King that by the grace of the Lord he still remembered all the incidents of his past life. Due to the activities of his past life, Jaḍa Bharata was being very cautious and was therefore assuming the characteristics of a deaf and dumb man to avoid mingling with the material world. Association with the material modes of nature is very powerful. The bad association of materialistic men can be avoided only in the association of devotees.
(Srimad Bhagavatam-----5:12-----summary).

Sometimes a foolish person becomes disgusted with bad association and comes to the association of devotees and brāhmaṇas and takes initiation from a spiritual master. As advised by the spiritual master, he tries to follow the regulative principles, but due to misfortune he cannot follow the instructions of the spiritual master.
(Srimad Bhagavatam-----5:13:17-----purport).

Somehow or other, if one is attracted to Kṛṣṇa, whatever he does in devotional service is a permanent asset. Even if one falls down due to immaturity or bad association, his devotional assets are never lost. There are many examples of this—Ajāmila, Mahārāja Bharata, and many others. This Kṛṣṇa consciousness movement is giving everyone a chance to engage in devotional service for at least some time. A little service will give one an impetus to advance and thus make one's life successful.
(Srimad Bhagavatam-----5:14:43-----purport).

In Bhagavad-gītā (6.41) Kṛṣṇa says, śucīnāṁ śrīmatāṁ gehe yoga-bhraṣṭo 'bhijāyate: "Because of his previous connection with bhakti-yoga, a man is born into a prestigious family of brāhmaṇas or aristocrats." Having taken such a birth, one should utilize it to perfect bhakti-yoga. However, due to bad association one often forgets that his prestigious position has been given to him by the Supreme Personality of Godhead, and he misuses it by performing various kinds of so-called yajñas like kālī-pūjā or durgā-pūjā, in which poor animals are sacrificed. How such a person is punished is described herein.
(Srimad Bhagavatam-----5:26:25-----purport).

Ajāmila was a brāhmaṇa who because of bad association had given up all brahminical culture and religious principles. Becoming most fallen, he stole, drank and performed other abominable acts. He even kept a prostitute. Thus he was destined to be carried away to hell by the order carriers of Yamarāja, but he was immediately rescued simply by a glimpse of the chanting of the holy name Nārāyaṇa.
(Srimad Bhagavatam-----6:2:45-----purport).

The Lord assured Bali Mahārāja of all protection, and finally the Lord assured him of protection from the effects of bad association with the demons. Bali Mahārāja certainly became an exalted devotee, but he was somewhat anxious because his association was not purely devotional. The Supreme Personality of Godhead therefore assured him that his demoniac mentality would be annihilated. In other words, by the association of devotees, the demoniac mentality is vanquished.
(Srimad Bhagavatam-----8:22:36-----purport).

By gradually associating with the members of the Kṛṣṇa consciousness movement, simply by taking prasāda and taking part in chanting of the Hare Kṛṣṇa mantra, ordinary persons are being considerably elevated. Saubhari Muni regrets that he had bad association even in the deepest part of the water. Because of the bad association of the sexually engaged fish, he fell down. A secluded place is also not secure unless there is good association.
(Srimad Bhagavatam-----8:6:51-----purport).

Formerly, in his previous birth, Asamañjasa had been a great mystic yogi, but by bad association he had fallen from his exalted position. Now, in this life, he was born in a royal family and was a jāti-smara; that is, he had the special advantage of being able to remember his past birth. Nonetheless, he wanted to display himself as a miscreant, and therefore he would do things that were abominable in the eyes of the public and unfavorable to his relatives. He would disturb the boys sporting in the River Sarayū by throwing them into the depths of the water.
(Srimad Bhagavatam-----9:8:15-16-----purport).

One should not attempt to imitate such exalted devotees. Rather, everyone should endeavor to preach the cult of Śrī Caitanya Mahāprabhu in all parts of the world and thus become successful in spiritual life. One who is not very expert in preaching may chant in a secluded place, avoiding bad association, but for one who is actually advanced, preaching and meeting people who are not engaged in devotional service are not disadvantages. A devotee gives the nondevotees his association but is not affected by their misbehavior. Thus by the activities of a pure devotee even those who are bereft of love of Godhead get a chance to become devotees of the Lord one day.
(Sri Caitanya Caritamrta-----1:7:92-----purport).

Even if, by some bad association, he falls down while executing devotional service, or if he doesn't finish the complete course of devotional service and dies untimely, still he is not at a loss. A person who is simply discharging his occupational duty in varṇa and āśrama, however, with no Kṛṣṇa consciousness, practically does not gain the true benefit of human life."
(Nectar of Devotion).

This is the way to cultivate devotional service properly; therefore in this verse Śrīla Rūpa Gosvāmī has advised us how to treat various devotees. We can see from practical experience that there are different types of Vaiṣṇavas. The prākṛta-sahajiyās generally chant the Hare Kṛṣṇa mahā-mantra, yet they are attached to women, money and intoxication. Although such persons may chant the holy name of the Lord, they are not yet properly purified. Such people should be respected within one's mind, but their association should be avoided. Those who are innocent but simply carried away by bad association should be shown favor if they are eager to receive proper instructions from pure devotees, but those neophyte devotees who are actually initiated by the bona fide spiritual master and are seriously engaged in carrying out the orders of the spiritual master should be offered respectful obeisances.
(Nectar of Instruction).

When Rūpa and Sanātana compared themselves to Jagāi and Mādhāi, they found themselves inferior because the Lord had no trouble in delivering two drunken brothers. This was so because, despite the fact that they were addicted to sinful activity, in other ways their life was brilliant. They belonged to the brāhmaṇa caste of Navadvīpa, and such brāhmaṇas were pious by nature. Although they had been addicted to some sinful activities due to bad association, those unwanted things could vanish simply because of the chanting of the holy name of the Lord.
(Sri Caitanya Caritamrta-----2:1:194-----purport).

“Cheating oneself and cheating others is called kaitava. Associating with those who cheat in this way is called duḥsaṅga, bad association. Those who desire things other than Kṛṣṇa's service are also called duḥsaṅga, bad association.
(Sri Caitanya Caritamrta-----2:24:99-----purport).