One day imam Mūsá ibn Ja‘far was passing by an alley who heard a singing sound from a house. At the same time the servant came out to throw the trash somewhere next to the house. Seeing the servant imam asked him: "is the owner of this house a slave or freeman?" the servan replied. He is free.imam then continued and said: it is obvious that he is free otherwise he wouldn, t spread the layout of sins and pleasure and hedonism and he would fear of his ownerand lord.the servant entered the house, His master asked him:"Why did you come late?"
The servant recounted the story and said: I saw a man that the affects worship was visible on his face.he asked me something about the owner of the landlord and I answered.the landlord pondered upon hearing the story and after a few moments he came to himself and then ran barefoot after the man.when he got to Imam he realized that he is Mūsá ibn Ja‘far so he expressed remorse and decided to repent. And from that day on he no longer wore shoes in honour of the day he repented bare foot and became well-known as “Boshr Hafi”.
source : erfan.ir