Musnad Abu Ya'la al-Mawsili 117:119

Al-Muqaddami Abdullah bin Abi Bakr, the brother of Muhammad bin Abi Bakr, narrated to us, saying: Ja'far narrated to us, from Thabit, from Anas, who said: When the Messenger of Allah (may Allah bless him and grant him peace) entered Makkah, the people looked up at him, so he lowered his head upon his saddle out of humility.