Al-Bara' bin 'Azib said, "The Prophet (may peace and blessings of Allah swt shower on him) 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. 

Bukhari :: Book 3 :: Volume 43 :: Hadith 625