AL BARA' ibn Azib (may Allah be pleased with him) relates: 'The Prophet (May Allah's peace & blessings be upon him, his family & companions) asked us to do seven things: to visit the sick, to follow funeral processions, to pray for Allah's mercy for someone who sneezes (by saying yarhamukallah), to return greetings, help those who are wronged, accept invitation, and fulfil our oaths and promises'. (Bukhari, Muslim)