Sahih Adab al-Mufrad

712/923-(Sahih) From Ibn Mas'ud, from the Prophet, peace be upon him, who said: "Four are due from a Muslim to a Muslim: he visits him when he is sick, attends his funeral when he dies, answers him when he invites, and blesses him when he sneezes."

713/924- (Sahih) From Al-Bara' ibn 'Azib who said: "The Messenger of Allah, peace and blessings be upon him, commanded us with seven things and forbade us from seven. He commanded us to visit the sick, to follow the funerals, to respond to the sneezer, to fulfill the oath, to help the oppressed, to spread peace, and to answer the invitation. And he forbade us from gold rings, silver vessels, Mayathir, Qassiy, Istabraq, Dibaaj, and silk."