Musnad Ahmad 1060:94

'Attab narrated to me, Abdullah narrated to us, Ibn Lahi'ah narrated to us, Bukayr ibn al-Ashajj narrated to us, that his father narrated to him, that 'Ubayd ibn Ta'la narrated to him, that he heard Abu Ayyub saying: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade the *sabr* (tying up) of the animal."