"The rights of one Muslim over another Muslim are six." Someone asked, "What are they?" The Holy Prophet replied, "When you meet him you greet him with peace, when he invites you, you accept his invitation, when he consults you in a matter, you give him sincere advice, when he sneezes and praises Allah, you ask Allah to have mercy on him, when he is sick, you visit him and when he passes away you accompany him (i.e. you join in his funeral)." (Bukhari)