وَعَنْ ثَوْبَانَ رضى الله عنه
قَالَ: «كَانَ رَسُولُ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: إِذَا اِنْصَرَفَ مِنْ صَلَاتِهِ اِسْتَغْفَرَ اَللَّهَ ثَلَاثًا، وَقَالَ: «اَللَّهُمَّ أَنْتَ اَلسَّلَامُ وَمِنْكَ اَلسَّلَامُ. تَبَارَكْتَ يَا ذَا اَلْجَلَالِ وَالْإِكْرَامِ» رَوَاهُ مُسْلِمٌ. 11 صحيح
Whenever the Messenger of Allah (sallallahu alayhi wa sallam) finished his prayer, he used to say after asking Allah’s forgiveness three times: “O Allah, You are as-Salam (One Free from every defect), and as-Salam (safety from every evil) is (sought) from You. Blessed are You, O Possessor of glory and honour.”.
Bulugh al-Maram 391, Book 2, The Book of Prayer, Hadith 212. 1 min read