Jami` at-Tirmidhi, Hadith 2856 ⓘ
Narrated Abu Salih: "I asked 'Aishah and Umm Salamah about which deed did the Messenger of Allah like to do most. They said: 'Whatever he could do regularly, even if it was little.'"
حَدَّثَنَا أَبُو هِشَامٍ الرِّفَاعِيُّ، حَدَّثَنَا ابْنُ فُضَيْلٍ، عَنِ الأَعْمَشِ، عَنْ أَبِي صَالِحٍ، قَالَ سُئِلَتْ عَائِشَةُ وَأُمُّ سَلَمَةَ أَىُّ الْعَمَلِ كَانَ أَحَبَّ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَتَا مَا دِيمَ عَلَيْهِ وَإِنْ قَلَّ . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ غَرِيبٌ مِنْ هَذَا الْوَجْهِ .
also referenced under: Book 43, Hadith 3094 (In-Book) & Volume 5, Book 41, Hadith 2856 (DarusSalam)