C. F. Keil and Franz Delitzsch on Numbers 16:31-33

Num 16:31-33

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 Num 18:31; Exo 12:3. “All the men belonging to Korah” were his servants; for, according to Num 26:11, his sons did not perish with him, but perpetuated his family (Num 26:58), to which the celebrated Korahite singers of David’s time belonged (1Ch 6:18-22; 1Ch 9:19).