348.Anas said reported, The Messenger of Allah (peace be upon him) said: "Do not hate one another and be not jealous of one another and do not boycott one another, and be servants of Allah (as) brethren; and it is not lawful for a Muslim that he should sever his relations with his brother for more than three days."
(Bukhari).
(A Manual of Hadith by. Maulana Muhammad Ali).