Musnad Abu Ya'la al-Mawsili 238:12

Muhammad ibn Abi Bakr al-Muqaddami and Ishaq narrated to us, they said: Umar ibn Ali narrated to us, he said: Amr, the freed slave of the family of Mandhur ibn Sayyar, narrated to us, from Asim ibn Ubayd Allah, from Abdullah ibn Amir ibn Rabi'ah, from his father: That the Prophet, peace and blessings of Allah be upon him, was performing Tawaf around the House (the Kaaba) when the strap of his sandal broke. He took out a piece of leather for the strap of his sandal and went to tie it onto the sandal of the Prophet, peace and blessings of Allah be upon him. He (the Prophet) snatched it away and said: "This is favoritism (atharah), and I do not like favoritism."