How much less in them that dwell in houses of clay! rather, hew muck more cloth he not put trust in them that inhabit houses of clay! i.e. "earthly bodies," bodies made out of the dust of the ground (Genesis 2:7; setup, Job 33:6).
Whose foundation is in the dust; i.e." whose origin was the dust of the ground," which were formed from it and must return to it, according to the words of Genesis 3:19, "Dust thou art, and unto dust thou must return."
Which are crushed before the moth. This is somewhat obscure. It may mean, "which are so fragile that a moth, a fly, or other weak creature may destroy them," or "which are crushed with the same ease with which a moth is crushed and destroyed."