The Messenger of Allaah (sal-Allaahu 'alayhe wa sallam) said: "You shall not enter paradise until you believe, and you shall not believe until you love one another. Shall I not inform you of something, if you were to act upon it, you will indeed achieve mutual love for one another? Spread salaam amongst yourselves."  'Ammaar (radhi-yAllaahu 'anhu) said: "Three characteristics, whoever combines them, has completed his faith: to be sincerely just, to spread greetings to all people and to spend [charitably] out of the little you have."  'Abdullaah Ibn 'Amr (radhi-yAllaahu 'anhu) reported that a man asked The Prophet (sal-Allaahu 'alayhe wa sallam): "Which Islaam is the best?". He (sal-Allaahu 'alayhe wa sallam) replied: Feed [the poor] , and greet those whom you know as well as those whom you do not."