The Book of Prayers (Kitab Al-Salat)

Muslim :: Book 4 : Hadith 1456

Qatada narrated it on the authority of Anas b. Malik that the Apostle of Allah (may peace be upon him) said: He who forgets tte prayer, or he slept (and it was omitted), its expiation is this only that he should observe it when he remembers it.