Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "The Muslim owes his fellow Muslim six (things): when you meet him, greet him; when he invites you, accept his invitation; when he asks for your advice, give him advice; when he sneezes and praises Allah, say: May Allah have mercy on you; when he is ill, visit him; and when he dies, follow his funeral."
Explanation:
Islam is the religion of love, affection, and brotherhood. It encourages and promotes these traits. For this reason, it legislated the means that bring about the realization of these noble goals. One of the most important of these goals is to fulfill the social duties among the Muslim individuals, by extending the greetings of peace profusely, accepting the invitation, giving advice if one is consulted about a matter, saying "May Allah have mercy upon you" to someone who sneezes and praises Allah, visiting the sick, and following funerals.