Sunan an-Nasa'i, Volume 2, Book 20, Hadith 1785 (DarusSalam) ⓘ

It was narrated from Sa'eed bin Jubair, from a man who he thought was good, that : Aishah, may Allah (SWT) be pleased with her, told him that the Messenger of Allah said: "There is no man who habitually prays at night, then sleep overwhelms him, but Allah (SWT) will record for him the reward of his prayer, and his sleep is a charity given to him."

أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، عَنْ مَالِكٍ، عَنْ مُحَمَّدِ بْنِ الْمُنْكَدِرِ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنْ رَجُلٍ، عِنْدَهُ رِضًا أَخْبَرَهُ أَنَّ عَائِشَةَ رضى الله عنها أَخْبَرَتْهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ مَا مِنِ امْرِئٍ تَكُونُ لَهُ صَلاَةٌ بِلَيْلٍ فَغَلَبَهُ عَلَيْهَا نَوْمٌ إِلاَّ كَتَبَ اللَّهُ لَهُ أَجْرَ صَلاَتِهِ وَكَانَ نَوْمُهُ صَدَقَةً عَلَيْهِ ‏" ‏ ‏.‏