Who or what decides our moral compass? what makes us think this act is evil and this is good? Or maybe the more important question would be what is the need of morality?
Morality is required simply for survival! yes it may seem a bit non-altruistic but the concept of morality doesn't come from religion or faith on some supernatural being watching over us and judging whether what we do is right or wrong. The concept is simply evolutionary. Being a social animal humans need to be altruistic simply to survive. And hence the idea of morality.
Its often the reasoning of theologists and those who have this blind faith in their religion that without religion morality doesn't exist. Without this concept of hell and heaven people could do whatever they wished without any kind of repercussions. The society would be anarchy, primeval and lawless. Without going into the long standing debate on the belief whether science and religion can cohabit in this 21st century (which according to me is strictly baseless simply because one is based on evidence and can be questioned while the other demands strict belief and faith on some scriptures with no evidence to show for the claims. To me the scriptures should be preserved as great works of art or fantasy- nothing more than the modern Lord of the Rings or Harry Potter. Yes, given enough time Pottermania might even give rise to a new religion where Dumbledore is the god, Potter his soldier and Voldemort the new Satan. All one needs is a group of motivated, dedicated and misled pottermaniac jihadis. If you think I am joking just look at how Constantin the pagan Roman emperor promoted Catholic Christianity)
But why should we-the most logical species of them all need this "faith" to bind us and make sure we do "good" and not "evil". After all a strict implementation of law and execution of justice should be enough to restrain evil men from committing crimes and leading good men on the path of "honesty", "justice" and a dignified life. Didn't a Nobel laureate say " Religion is an insult to humanity. Good men do good things and evil men do evil things. But Religion makes a good man do evil things" (My god is better than yours! My scripture is holier than yours! You should not do that because that is forbidden in the scripture! If you do not follow my God I am going to rape and kill you!)
My point is that any reasoning that "I do not torture, pillage, rape and murder you simply because I fear God will send me to hell in afterlife" is simply stupid. If someone needs to fear someone to control that kind of a violent and poisonous beast inside him a strict law of the land should be enough to dissuade him or punish him in the event he commits the crime actually. For others, plain old logic is enough for the very thought to never even take form.
So discard religion. Embrace logic. Encourage questions. And if your argument still is "something that is believed by so many people all over the world and something that science hasn't been able to disprove cannot be wrong or non-existent" then just recall what people all over the world believed regarding the Sun and the Earth before Copernicus and the fact that anything that can't be disproved does not necessarily be existent.
Because someday someone with a very high intelligence and an imposing personality might come and say "There is only one god and that is a flying spaghetti monster. The heaven is where there is a beer fountain and a stripper factory. The hell is the same as heaven except the beer is stale and the strippers have STDs" and ask you to kill all people who do not renounce their faiths in other religions and accept this religion in the name of the Church of the flying spaghetti monster. After all there is no way to disprove his theory is incorrect or flawed.
P.S. What is wrong with religion? Just look at Jerusalem: destroyed twice, besieged 23 times, attacked 52 times, and captured and recaptured 44 times.
Disclaimer: I personally stand somewhere between atheism and agnosticism. And this post I am not going to apologize to someone's hurt sentiments because of his/her religious views because to me the very idea of religion is a non-subject. I can't apologize to every lunatic who thinks magic exists simply because it can't be proven that it doesn't.