It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) came out during his illness with a band tied around his head. He (peace and blessings be upon him) sat on the pulpit, praised and glorified Allah, then said: "There is no one among the people who has done me greater favour with his life and his wealth than Abu Bakr bin Abi Quhafah. If I were to take anyone from among the people as a khalil (intimate friend), I would have taken Abu Bakr, but the brotherhood of Islam is better." Then he said: "Let no door remain in the mosque except that it is closed, except the door of Abu Bakr."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11888