عَنِ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا قَالَ: كُنْتُ أَعْرِفُ انْقِضَاءَ صَلَاةِ رَسُولِ اللَّهِ صَلَّى الله عَلَيْهِ وَسلم بِالتَّكْبِيرِ

Thauban said that when God’s Messenger finished his prayer he asked forgiveness three times and said, “O God, Thou art Peace, and peace comes from Thee. Blessed art Thou, O Possessor of glory and honour.”Muslim transmitted it.