Al-Adab Al-Mufrad, Book 40, Hadith 925 (English) ⓘ

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."

وَعَنْ إِسْمَاعِيلَ بْنِ جَعْفَرٍ، عَنِ الْعَلاَءِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللهِ صلى الله عليه وسلم قَالَ‏:‏ حَقُّ الْمُسْلِمِ عَلَى الْمُسْلِمِ سِتٌّ، قِيلَ‏:‏ مَا هِيَ يَا رَسُولَ اللهِ‏؟‏ قَالَ‏:‏ إِذَا لَقِيتَهُ فَسَلِّمْ عَلَيْهِ، وَإِذَا دَعَاكَ فَأَجِبْهُ، وَإِذَا اسْتَنْصَحَكَ فَانْصَحْ لَهُ، وَإِذَا عَطَسَ فَحَمِدَ اللَّهَ فَشَمِّتْهُ، وَإِذَا مَرِضَ تَعُودُهُ، وَإِذَا مَاتَ فَاتَّبِعْهُ‏.‏