Mishkat al-Masabih
Mishkat al-Masabih 45
Arabic hadith text
وَعَنْ أَبِي أُمَامَةَ أَنَّ رَجُلًا سَأَلَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَا الْإِيمَانُ قَالَ إِذَا سَرَّتْكَ حَسَنَتُكَ وَسَاءَتْكَ سَيِّئَتُكَ فَأَنْتَ مُؤْمِنٌ قَالَ يَا رَسُولَ اللَّهِ فَمَا الْإِثْمُ قَالَ إِذَا حَاكَ فِي نَفْسِكَ شَيْءٌ فَدَعْهُ» . رَوَاهُ أَحْمد
Translation
Abu Umama reported that a man asked the Messenger of God, “What is faith?” He said, “When your good deed pleases you and your bad deed grieves you, you are a believer.” The man said, “Messenger of God, what is sin?” He said, “When something troubles your conscience, leave it.” Ahmad narrated it.