Tafsir of As-Saffat 37:21

(This is the Day of Judgment which you used to deny.)

This speech of the angels is a response to them by way of rebuke and reprimand. It is also said that it is from the speech of some of them to others. Abu Hatim paused at "Woe to us," and considered what follows it to be the speech of Allah (Exalted is He), or the speech of the angels (peace be upon them) to them, as if they answered them that wailing and lamenting are of no avail.

"The Judgment" (al-fasl) means the verdict, or the separation between the doer of good and the doer of evil, and the distinguishing of each from the other without a verdict.