مُوَطَّأُ مَالِكٍ
Muwatta Malik 425
Shortening the Prayer
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّهَا قَالَتْ كَانَ أَحَبُّ الْعَمَلِ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم الَّذِي يَدُومُ عَلَيْهِ صَاحِبُهُ .
Yahya related to me from Malik from Hisham ibn Urwa from his father that A'isha, the wife of the Prophet, (ﷺ), said, "The actions which the Messenger of Allah, (ﷺ), loved most were those which were done most constantly."
Arabic/English book reference: Book 9, Hadith 92