It is narrated from Sayyiduna Abu Ayyub Ansari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "It is not proper for a Muslim to abandon meeting his Muslim brother, that is, to leave him for more than three days (i.e., to hold a grudge for more than three days), or if he meets him, he does not look at him, or if the other meets him, he does not look at him. The better of the two is the one who greets (says Salam) first."