Sahih Muslim 2553
Sahih
Sahih Muslim — Hadith 2553
Narrated by An-Nawwas ibn Sam'an
الْبِرُّ حُسْنُ الْخُلُقِ وَالإِثْمُ مَا حَاكَ فِي صَدْرِكَ وَكَرِهْتَ أَنْ يَطَّلِعَ عَلَيْهِ النَّاسُ
Translation
The Prophet said: 'Righteousness is good character, and sin is that which wavers in your heart and which you dislike people finding out about.'
Commentary
This hadith provides a remarkably accessible definition of morality. Righteousness (birr) is equated with good character — not merely ritual compliance. Sin is identified through one's own moral conscience: the inner discomfort and desire to hide an act reveal its sinful nature.