Bhagwad Gita
Chapter 9, Verse 30
अपि चेत्सुदुराचारो भजते मामनन्यभाक्।
साधुरेव स मन्तव्यः सम्यग्व्यवसितो हि सः।।9.30।।
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.