كتاب السهو
4
Forgetfulness in Prayer

Yahya related to me from Malik that he had heard that the Messenger of Allah, may Allah bless him and grant him peace, said, "I forget or I am made to forget so that I may establish the sunna."


وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ إِنِّي لأَنْسَى أَوْ أُنَسَّى لأَسُنَّ ‏"‏ ‏.‏
Sunnah.com reference : Book 4, Hadith 2
USC-MSA web (English) reference : Book 4, Hadith 2
Arabic reference : Book 4, Hadith 224