´It was narrated from Hudhaifah that the Prophet (ﷺ) used to say between the two prostrations:` “Rabbighfir li, Rabbighfir li (O Lord forgive me, O Lord forgive me).”
Hadith ReferenceSunan Ibn Majah / Establishing the Prayer and the Sunnah Regarding Them / Hadith: 897
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح مسلم