⦗18⦘ “Do they await anything but the Hour, that it should come upon them suddenly? Its portents have already appeared. But when it comes upon them, how will they then benefit from taking heed?”

That is: Do these deniers expect anything but “the Hour, that it should come upon them suddenly”—unexpectedly, while they are unaware? “Its portents have already appeared”—that is, the signs indicating that it is near.

“But when it comes upon them, how will they then benefit from taking heed?” That is, once the Hour comes upon them and their allotted lives have ended, how will they be able to take heed and seek to make amends? The opportunity will have passed, and the time for taking heed will be gone. They were granted lives long enough for anyone willing to take heed to do so, and the warner came to them.

This encourages preparation before death comes unexpectedly, for a person’s death marks the onset of his Hour.