Musannaf Ibn Abi Shayba 35:74

'Abd al-Rahim narrated to us, from Muhammad ibn Kurayb, from Kurayb, from Ibn 'Abbas, from Sinan ibn 'Abd Allah al-Juhani, that his paternal aunt narrated to him that she came to the Prophet, peace and blessings of Allah be upon him, and said: "O Messenger of Allah, my mother has died, and she had a vow to walk to the Ka'bah." The Prophet, peace and blessings of Allah be upon him, said: "Are you able to walk on her behalf?" She said: "Yes." He said: "Then walk on behalf of your mother." She said: "Will that suffice for her?" He said: "Yes. Tell me, if she had a debt, would you pay it off, and would it be accepted from you?" She said: "Yes." The Prophet, peace and blessings of Allah be upon him, said: "Then the debt of Allah is more worthy [of being fulfilled]." And it was mentioned that Abu Hanifah said: "That does not suffice."