Do we need religion for morality? Morality without religion?

Some time ago I answered this Question (https://islam.stackexchange.com/questions/11929/as-an-atheist-what-awaits-me-after-death/11931#11931) based on my own knowledge! The questioner commented that I am very wrong and **we do not need religion for morality** as I had referred to that in my answer. I was surprised since it was like one of my basic beliefs and very natural for me but then I understood I had no real proof for that (:P I have some but not so convincing). I need to add that I think this is a mistake that to accept we can have morality without a religion, then one can say why there are religions for then?? And then one can result there is no God!! So I want you to give me these proofs from Muslims point of view, Thanks.