A man asked the Prophet , “What sort of deeds or (what qualities of) Islam are good?” The Prophet replied, ‘To feed (the poor) and greet those whom you know and those whom you do not Know. There is much reward in feeding the poor but feeding Iftar to the poor in Ramadan has even greater reward.(See Hadith No. 27).
Volume 1, Book 2, Number 11 : Narrated by 'Abdullah bin 'Amr