It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: Every Muslim has six rights over another Muslim. Someone asked, "O Messenger of Allah, what are those rights?" The Holy Prophet (peace and blessings be upon him) said: (1) When you meet him, greet him with Salam; (2) If he invites you, accept his invitation; (3) If he seeks your advice, give him sincere advice; (4) If he sneezes, respond to him; (5) If he falls ill, visit him; (6) If he dies, attend his funeral.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 8845