Isaiah 37:27

Therefore their inhabitants were of small power, they were dismayed and confounded: they were as the grass of the field, and as the green herb, as the grass on the housetops, and as corn blasted before it be grown up.

Therefore - Not because of thy power, but because I made them unable to withstand thee.

(As) the grass - which easily withers (; ).

On the housetops - which, having little earth to nourish it, fades soonest (Psalms 129:6).

Corn blasted before it be grown up.