Abu Hurayra reported that the Messenger of Allah, may Allah blesshim 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 greethim when he meets him, to accept when he gives him an invitation, to givehim good counsel when he asks for advice, to wish mercy on him when hesneezes and says, 'Praise be to Allah,' to visit him when he is ill, andto join the funeral procession when he dies."
English reference: Book 40, Hadith 925
Arabic reference: Book 1, Hadith 925