Muhammad bin Muslim relates from Imam Baqir (a.s.) that the Imam said,
O Muhammad bin Muslim! Every sin of a Mu’min for which he has repented is forgiven. For the future after repentance and forgiveness they must continue good deeds. By Allah no one has this merit except the faithful.
I inquired; what if someone does Tawba and Istighfar and then commits a sin and again repents? In response, the Imam said,
O Muhammad bin Muslim! You know very well that a Mu’min can honestly be ashamed for his deeds. Then if he repents, will Allah not accept his Tawba?
I asked what if he sins a number of times? He said,
Even then his Tawba will be accepted. Allah (S.w.T.) will pardon his sins because He is very kind. He will surely accept repentance and overlook our misdeeds. Beware! You may not make a Mu’min disheartened.
Abu Basīr says: I requested Imam Ja’far Sadiq (a.s.) to explain what was ‘Tawba Nasūh’ ordered by Allah? He said,
“A repentance after which he never commits that sin again.”
I said, “Master! Is there anybody among us who would not sin ever again? The Imam replied,
“O Abu Basīr! Verily God loves His slave who gets deceived more and then repents over it.”