Musnad Abu Ya'la al-Mawsili 152:200

Abu al-Rabi’ narrated to us, Ya’qub bin Ibrahim narrated to us, Abu Hanifah narrated to us, from al-Haytham—Abu al-Rabi’ said: meaning Ibn Habib—who said: Abdullah said: "I have not lied since I accepted Islam, except for one lie." "I was saddling [a mount] for the Messenger of Allah (ﷺ), when a man from Ta’if came and said, 'Which mount is most pleasing to the Messenger of Allah (ﷺ)?' I said, 'The Ta’ifian one with the sloping shoulder.' And the Messenger of Allah (ﷺ) disliked it." "He said: 'When he had saddled it and brought it to him, he said, "Who saddled this for us?" They said, "The one you brought from Ta’if saddled it for you." He said, "Return the mount to Ibn Mas’ud."'"