Krishna has warned us,

api cet su-durācāro
bhajate mām ananya-bhāk
sādhur eva sa mantavyaḥ
samyag vyavasito hi saḥ

kṣipraṁ bhavati dharmātmā
śaśvac-chāntiṁ nigacchati
kaunteya pratijānīhi
na me bhaktaḥ praṇaśyati
(Bhagavad Gita 9.30 and 31)

Krishna says, “If My devotee, due to bad impressions of previous birth, commits the most abominable action but if is engaged in one pointed devotion to Me, consider him a sadhu, a saintly person. Because he will have repentance for that and that fire of repentance will burn all his sins to ashes quickly. He is to be considered saintly because by situating in his determination, quickly he will be righteous and will attain everlasting peace.”

Krishna says, “He was worshiping Me and now he has given up, no, he is still worshiping Me, he is worshiping Me with sincerity.” After 80 lakhs of births we have got this human birth and in human birth we did so many bad deeds. Those impressions were there. Due to those impressions, he might have done one wrong thing, very wrong thing, illicit connection with women, we may say, but don't disregard him because he will have repentance to the extreme, he did a great wrong thing and he will cry, he will pray for the grace to Guru Vaishnava. You wait for some time, he will become sādhu. He will get absolute bliss and transcendental realm, there it is written. “You should not behave with him harshly then I (Krishna) shall be displeased.” He is trying, he is trying his best. But there are waves of bad thoughts and good thoughts. And sometimes bad thoughts also come and by bad thoughts he might have done some wrong, because of the influence of that. “Do not take the decision to ignore him, then you will be loser, I (Krishna) shall be displeased.” If God is displeased then you will not get the actual benefit. God is seeing that the person is trying, trying, trying, but due to previous bad impressions he might have done something wrong, api cet su-durācāro bhajate mām ananya-bhāk but he did not give up his bhajan, he is doing bhajan, worshiping, ananya-bhāk with one-pointed devotion (not worshipping any demi-god) or he has not taken another way of worship—yoga-patha, karma-patha, jnana-patha. No, no, he is not doing that. He is doing śuddha-bhakti (unalloyed devotion), he is trying to please, yet there may be some mishap. “Don't disrespect him. If you disrespect him, saying something against him then I shall be displeased. Your objective is to please Me.” With that one warning and He ordered Arjuna, “Go to the karmis, to the jnānis, to the yogis and to the worshipers of demi-gods and declare, taking the oath that My devotee, will not be ruined, will never be ruined. Declare it everywhere.”

The life of śuddha-bhakta is one-pointed devotion to Supreme Lord. That he is sticking to and trying to do. So that life (sādhan) is there, he has not given up. Those who are deceitful they do all these criminal works and they have got no repentance. They are deceitful, hypocrites, they will go to hell. But there may be some devotees very sincere, but unable to check themselves sometimes maybe. Don't speak ill of them. (Krishna says,) “If you do so then I shall be dissatisfied.”