But they [who reject My messages are wont to] ask, When is that promise [of God's judgment] to be fulfilled? [Answer this, O you who believe in it,] if you are men of truth!"

They say: "When will this promise come to pass, if ye are telling the truth?"

And they say: When will this promise (be fulfilled), if ye are truthful?

And they say: When will this threat come to pass, if you are truthful?

And they say, "When is this promise, if you should be truthful?"