John Calvin Commentary Numbers 16:28

"And Moses said, Hereby ye shall know that Jehovah hath sent me to do all these works; for [I have] not [done them] of mine own mind." — Numbers 16:28 (ASV)

And Moses said, Hereby you shall know. Moses now begins to show more clearly why he has brought the rebels to this open contest: namely, that God might sanction before all the people, by a terrible exertion of His power, the system He Himself established.

For it was no ordinary act of confidence to concede victory to His enemies unless the earth were to swallow them up alive. But, since this was to be a most conspicuous judgment of God, he rouses their attention with the striking words he uses.

If they were to be cut off by a sudden death, he would have justly boasted that his cause was approved by God. But not content with this, he desires to be considered a mere impostor if they should die the common death of men. To express the strangeness of the miracle, by which people's senses would be astonished, he emphatically uses the word create⁹⁹, as if to say that the manner of their death would be no less unusual than if God were to add something new to His creation and change the face of the world.

Thus David, when he prays that his enemies should go down alive into hell (infernos) or the grave, seems to allude to this history (Psalms 55:23). For although that descent is understood to mean sudden death overtaking the wicked in a moment in the midst of their happiness and security, still, he at the same time indicates by it this horrible retribution, which had occurred in times past, since memorable punishments become proverbial instances of God’s wrath.

⁹⁹ A.V., “Make a new thing;” margin, “Create a creature.”, “Make a new thing;” margin, “Create a creature.”