and who remember their Sustainer far into the night, prostrating themselves and standing;
Al-Furqan (The Criterion) Verse 64
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
Sahih Bukhari: Volume 1, Book 2, Number 11