عَنْ أَبِي ذَرٍّ رَضِيَ اللَّهُ عَنْهُ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ أَوْصِنِي قَالَ إِذَا عَمِلْتَ سَيِّئَةً فَأَتْبِعْهَا حَسَنَةً تَمْحُهَا قَالَ قُلْتُ يَا رَسُولَ اللَّهِ أَمِنَ الْحَسَنَاتِ لَا إِلَهَ إِلَّا اللَّهُ قَالَ هِيَ أَفْضَلُ الْحَسَنَاتِ
It is narrated from Sayyiduna Abu Dharr (may Allah be pleased with him), he says: I said, "O Messenger of Allah! Advise me." The Prophet (peace and blessings be upon him) said: "When you commit a bad deed, then follow it up with a good deed, so that it may erase the effect of that bad deed." I said, "O Messenger of Allah! Is 'La ilaha illallah' (There is no god but Allah) also a good deed?" The Prophet (peace and blessings be upon him) said: "It is the most virtuous of good deeds."