بِسْمِ اللهِ الرَّحْمنِ الرَّحِيمِ
The Messenger of Allah (صلى الله عليه و سلم ) commanded us to do seven things:
to visit the sick, to follow the funeral (of a dead believer), to invoke the Mercy of Allah upon one who sneezes (ie. by saying to him: Yarhamuk-Allah), to support the weak, to help the oppressed, to promote the greeting of 'As-Salamu ' Alaikum', and to help those who swear to do something to keep their oaths.
[Al Bukhari and Muslim]