Thawbannarrated that when he finished his prayer, the Messenger ofAllah(ﷺ) would ask for forgiveness three times, then he would say:
"Allahumma Antas-Salam wa minkas-salam tabarakta ya Dhal-jalaliwal-ikram" (O Allah, You are As-Salam and from You is all peace,Blessedare You O Possessor of majesty and honour)." (JA)
English reference (JA): Vol. 1, Book 5, Hadith 928 (JA)
Arabic reference (JA): Book 5, Hadith 981 (JA)