Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 1629
'Umar b. Khattab reported Allah's Messenger (may peace be upon him) as saying: Should anyone fall asleep and fail to recite his portion of the Qur'an, or a part of it, if he recites it between the dawn prayer and the noon prayer, it will be recorded for him as though he had recited it during the night.