If you actually ARE familiar with the Koran, you should be able to cite your source.......you can't, because there is no such statement made in the Koran--killing is ONLY authorized in self-defense.

What the Koran actually says is this:

The Disbelievers

In the name of Allah, the Beneficent, the Merciful.
[109.1] Say: O unbelievers!
[109.2] I do not serve that which you serve,
[109.3] Nor do you serve Him Whom I serve:
[109.4] Nor am I going to serve that which you serve,
[109.5] Nor are you going to serve Him Whom I serve:
[109.6] To you your religion and to me my religion.

You really SHOULD retract your statement, not just because it's incorrect and an insult to Muslims, but because such statements can encourage hatred toward the people of that religion.

It's the right thing to do.