They, and all that appertained to them, went down alive into the pit, and the earth closed upon them: and they perished from among the congregation.

Wesley's Notes

16:33 Into the pit - Into the earth, which first opened itself to receive them, and then shut itself to destroy them.

Matthew Henry's Concise Commentary

16:23-34 The seventy elders of Israel attend Moses. It is our duty to do what we can to countenance and support lawful authority when it is opposed. And those who would not perish with sinners, must come out from among them, and be separate. It was in answer to the prayer of Moses, that God stirred up the hearts of the congregation to remove for their own safety. Grace to separate from evil-doers is one of the things that accompany salvation. God, in justice, left the rebels to the obstinacy and hardness of their own hearts. Moses, by Divine direction, when all Israel were waiting the event, declares that if the rebels die a common death, he will be content to be called and counted an imposter. As soon as Moses had spoken the word, God caused the earth to open and swallow them all up. The children perished with their parents; in which, though we cannot tell how bad they might be to deserve it, or how good God might be otherwise to them; yet of this we are sure, that Infinite Justice did them no wrong. It was altogether miraculous. God has, when he pleases, strange punishments for the workers of iniquity. It was very significant. Considering how the earth is still in like manner loaded with the weight of man's sins, we have reason to wonder that it does not now sink under its load. The ruin of others should be our warning. Could we, by faith, hear the outcries of those that are gone down to the bottomless pit, we should give more diligence than we do to escape for our lives, lest we also come into their condemnation.