And it came to pass, as he had made an end of speaking all these things,.... As soon as he had finished his discourse, which was addressed to the congregation, and, according to Josephus (u), after a long prayer to God, which that writer gives at large; immediately so it was:
that the ground clave asunder that was under them; on which they stood, not from any natural cause, as by subterranean volcano, forcibly making their way and bursting the earth, and so getting vent, which has been thought to be the cause of earthquakes; but this was by the immediate hand and almighty power of God, and came to pass just as Moses suggested it would, and as soon as he had uttered his words, which made it the more observable.
(u) Antiqu. l. 4. c. 3. Sect. 2.

And immediately the earth clave asunder, and swallowed them up, with their families and all their possessions, and closed above them, so that they perished without a trace from the congregation. אתם refers to the three ringleaders. "Their houses;" i.e., their families, not their tents, as in Numbers 18:31; Exodus 12:3. "All the men belonging to Korah" were his servants; for, according to Numbers 26:11, his sons did not perish with him, but perpetuated his family (Numbers 26:58), to which the celebrated Korahite singers of David's time belonged (1-Chronicles 6:18-22; 1-Chronicles 9:19).