Musnad Ahmad 2420

It was narrated that Ibn ‘Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) came out during his final illness with a cloth wrapped around his head and sat on the minbar. He praised and glorified Allah then he said: "There is no one who supported me by his actions and with his wealth more than Abu Bakr bin Abi Quhafah. If I were to take a close friend (khaleel) among people, I would have taken Abu Bakr as a close friend. But the brotherhood of Islam is better. Block up for me every door into this mosque, except the door of Abu Bakr."