It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A Muslim has six rights over another Muslim: when you meet him, greet him with salam; when he sneezes, respond to him; when he is ill, visit him; when he invites you, accept his invitation; when he passes away, attend his funeral; and like for him what you like for yourself, and be his well-wisher in his absence."
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 673
Hadith Gradingحکم دارالسلام:حسن لغيره، وهذا إسناد ضعيف لضعف الحارث الأعور