that a man asked the Messenger of Allah ﷺ, "What is Īmān (faith)?" He said, "If you are happy with your good deeds and are saddened by your bad deeds, then you are a believer." The man said, “O Messenger of Allah, then what is sin?” He said, "If something ˹you do˺ troubles you within, then you should abandon it." (Using translation from Aḥmad 22166)
رَجُلٌ يَا رَسُولَ اللهِ مَا الْإِيمَانُ؟ قَالَ إِذَا سَرَّتْكَ حَسَنَتُكَ وَسَاءَتْكَ سَيِّئَتُكَ فَأَنْتَ مُؤْمِنٌ قَالَ يَا رَسُولَ اللهِ فَمَا الْإِثْمُ؟ قَالَ إِذَا حَاكَ فِي صَدْرِكَ شَيْءٌ فَدَعْهُ