عَنْ ثَوبَانَ رَضِيَ اللّّهُ عَنْهُ قَالَ: كَانَ رَسُولُ اللّهِ صَلَّى اللّهُ عَلَيْهِ وَسَلَّمَ إِذَا انْصَرَف مِنْ صِلاتِهِ اسْتَغفَرَ ثَلاثًا وَقَالَ: «اللَّهُمَّ، أَنْتَ السَّلامُ، وَمِنْكَ السَّلامُ، تَبَارَكْتَ ذَا الْجَلالِ وَالْإِكْرَامِ» قِيلَ لِلأَوْزَاعِيِّ -وَهُوَ أَحَدُ رُوَاةِ الْحَدِيثِ-: كَيْفَ الاِسْتِغْفَارُ؟ قَالَ: يَقُولُ: أَسْتَغْفرُ اللّهَ، أَسْتَغْفِرُ اللّهَ. رَوَاهُ مُسْلِمٌ.

Thawban (may Allah be pleased with him) reported: When the Messenger of Allah (peace and blessings be upon him) finished his prayer, he would seek forgiveness three times and say: "O Allah, You are Peace, and from You comes peace. Blessed are You, O Possessor of majesty and honor." Al-Awza'i—one of the narrators of the hadith—was asked: How is the seeking of forgiveness done? He said: One says: I seek Allah's forgiveness, I seek Allah's forgiveness. Reported by Muslim.