Sahih al-Bukhari, Volume 3, Book 45, Hadith 688 (USC-MSA) ⓘ
Narrated Abu Huraira: The Prophet said, "One can ride the mortgaged animal because of what one spends on it, and one can drink the milk of a milch animal as long as it is mortgaged. "
حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا زَكَرِيَّاءُ، عَنْ عَامِرٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ كَانَ يَقُولُ " الرَّهْنُ يُرْكَبُ بِنَفَقَتِهِ، وَيُشْرَبُ لَبَنُ الدَّرِّ إِذَا كَانَ مَرْهُونًا " .
also referenced under: Book 48, Hadith 4 (In-Book) & Hadith 2511 (DarusSalam)