Muwatta Malik, Book 31, Hadith 64 (USC-MSA)

Yahya related to me from Malik from Zayd ibn Aslam from Said ibn al-Musayyab that the Messenger of Allah, may Allah bless him and grant him peace, forbade bartering live animals for meat.

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّ رَسُولَ اللَّهِ

sunnah.com

also referenced under: Book 31, Hadith 1356 (In-Book)