Riyad as-Salihin 153
'Umar bin Al-Khattab (May Allah be pleased with him) reported:
Messenger of Allah (ﷺ) said, "Should anyone fall asleep at night and fail to recite his portion of the Qur'an, or a part of it, if he recites it between the Fajr prayer and the Zuhr prayer, it will be recorded for him as though he had recited it during the night". [Muslim] .
وعن عمر بن الخطاب رضي الله عنه قال‏:‏ قال رسول الله صلى الله عليه وسلم‏:‏ ‏
"‏ من نام عن حزبه من الليل، أو عن شيء منه فقرأه ما بين صلاة الفجر وصلاة الظهر، كتب له كأنما قرأه من الليل‏"‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏