Al-Adab Al-Mufrad #927

Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "A Muslim owes another Muslim six duties." He was asked, "And what are they, Messenger of Allah?" He said, "To greet him when he meets him, to accept when he gives him an invitation, to give him good counsel when he asks for advice, to wish mercy on him when he sneezes and says, 'Praise be to Allah,' to visit him when he is ill, and to join the funeral procession when he dies."