صحیح ابن حبان
Ibn Hibban
كتاب الصلاة
Book of Prayer
فصل في قيام الليل - ذكر الخبر الدال على أن صلاة الليل جعلت للمصطفى صلى الله عليه وسلم نفلا بعد أن كان الفرض عليه في البداية
Section on night prayer – mentioning a report indicating that night prayer was made voluntary for the Prophet after initially being obligatory
1 hadith
Hadith 2552
Sa’d bin Hisham narrates this statement from Sayyidah Aisha (may Allah be pleased with her): Whenever the Prophet (peace and blessings be upon him) performed any prayer, he liked to perform it regularly. And if, due to sleep or illness or any other engagement such as difficulty, he was unable to perform the night voluntary prayers, then he would perform twelve rak’ahs during the day.