Surely Allah is not ashamed to set forth any parable-- (that of) a gnat or any thing above that; then as for those who believe, they know that it is the truth from their Lord, and as for those who disbelieve, they say: What is it that Allah means by this parable: He causes many to err by it and many He leads aright by it! but He does not cause to err by it (any) except the transgressors,

That it may warn him who would have life, and (that) the word may prove true against the unbelievers.

So when he brought to them the truth from Us, they said: Slay the sons of those who believe with him and keep their women alive; and the struggle of the unbelievers will only come to a state of perdition.