There is the story of a thief who went on a pilgrimage to a holy town, and on route he and the other pilgrims stopped to rest overnight at an inn. Being addicted to stealing, the thief began making plans to steal the other pilgrims’ baggage, but he thought, “I’m going on a pilgrimage, so it doesn’t seem appropriate that I should steal this baggage. No, I shall not do it.” Nonetheless, due to his habit, he could not keep his hands off the baggage.
So he picked up one person’s bag and placed it in another place, and then another person’s bag and placed it elsewhere. He spent all night placing different bags in different places, but his conscience bothered him so that he could not take anything from them. In the morning, when the other pilgrims awoke, they looked around for their bags and couldn’t find them. There was a great row, and eventually, one by one, they began to find the bags in various places.
After they were all found, the thief explained: “Gentlemen, I am a thief by occupation. Being that I am habituated to stealing at night, I wanted to steal something from your bags, but I thought that since I am going to this holy place, it is not possible to steal. So I may have rearranged the baggage, but please excuse me.” This is the characteristic of a bad habit. He does not want
to commit theft anymore, but because he is habituated, sometimes he does.
Thus, one who has decided to refrain from his immoral habits and make progress in Lord Krishna consciousness is considered a sadhu. Lord Krishna mentions in Bhagwat Gita:
“Even if one commits the most abominable actions, if he is engaged in devotional service, he is to be considered saintly because he is properly situated.”
~Source: B.G. (Ch.9, XXX)