Sahih Bukhari Volume 003, Book 043, Hadith Number 625.

Narated By Muawiya bin Suwald : I heard Al-Bara' bin 'Azib saying, "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. (See Hadith No. 753, Vol. 7)