Sahih Bukhari Volume 3, Book 46, Hadith 2446

حَدَّثَنَا سَعِيدُ بْنُ الرَّبِيعِ، حَدَّثَنَا شُعْبَةُ، عَنِ الأَشْعَثِ بْنِ سُلَيْمٍ، قَالَ سَمِعْتُ مُعَاوِيَةَ بْنَ سُوَيْدٍ، سَمِعْتُ الْبَرَاءَ بْنَ عَازِبٍ ـ رضى الله عنهما ـ قَالَ أَمَرَنَا النَّبِيُّ صلى الله عليه وسلم بِسَبْعٍ، وَنَهَانَا عَنْ سَبْعٍ‏.‏ فَذَكَرَ عِيَادَةَ الْمَرِيضِ، وَاتِّبَاعَ الْجَنَائِزِ، وَتَشْمِيتَ الْعَاطِسِ، وَرَدَّ السَّلاَمِ، وَنَصْرَ الْمَظْلُومِ، وَإِجَابَةَ الدَّاعِي، وَإِبْرَارَ الْمُقْسِمِ‏.‏

Narrated By Al-Bara' bin 'Azib : "The Prophet orders us to do seven things and prohibited us from doing seven other things." Then Al-Bara' mentioned the following: 1. To pay a visit to the sick (inquiring about his health). 2. To follow funeral processions. 3. To say to a sneezer, "May Allah be merciful to you" (if he says, "Praise be to Allah!"). 4. To return greetings. 5. To help the oppressed. 6. To accept invitations. 7. To help others to fulfill their oaths.