en_tn/num/16/28.md

By this you will know

Here "this" refers to what Moses will say next.

that swallows them up like a large mouth

Moses speaks as if the earth were alive and the opening in the ground into which these people would fall were a large mouth that would eat them. AT: "and they fall into it and are buried underneath the ground" (See: rc://en/ta/man/translate/figs-simile)