It is narrated from Aisha (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) said: "It is not appropriate for a Muslim to cut off relations with another Muslim for more than three days. When he meets him, he should greet him with salam three times. If each time the other does not respond to the salam, then (the one who offered salam) is absolved of the sin of breaking relations." Its chain is Hasan. Narrated by Abu Dawood.