Musnad Abu Ya'la al-Mawsili 167:8

Abu Khaythama narrated to us, Jarir narrated to us, from Mansur, from Mujahid, from Yusuf ibn al-Zubayr, a freed slave of the family of al-Zubayr, from Abdullah ibn al-Zubayr, who said: A man from Khath'am came to the Messenger of Allah (may Allah bless him and grant him peace) and said: "O Messenger of Allah, my father reached Islam while he was a very old man, unable to ride a mount, and the Hajj is prescribed upon him. Shall I perform Hajj on his behalf?" He said: "Are you the eldest of his children?" He said: "Yes." He said: "Do you see, if your father had a debt, would you pay it off? Would that suffice?" He said: "Yes." He said: "Then perform Hajj on his behalf."