Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he said: "A Muslim has a right over another Muslim that when he meets him, he should greet him with salam; when he sneezes and says «الحمدللہ», he should reply to him with «يرحمك الله»; when he invites him, he should accept his invitation; when he falls ill, he should visit him; when he dies, he should attend his funeral, and in his absence, he should wish well for him."
Hadith Referenceمسند اسحاق بن راهويه / كتاب البر و الصلة / 775
Hadith Takhrij«بخاري ، رقم : 6222 ، 5175 ، 2445 ، 1239 . مسلم ، كتاب السلام ، باب من حق المسلم للمسلم رد السلام ، رقم : . . . ، سنن ابوداود ، رقم : 5030 . سنن ترمذي ، رقم : 2736 .»