Charles Ellicott Commentary 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 a field [of grain] before it is grown up." — Isaiah 37:27 (ASV)

Therefore. —Better, and.

They were as the grass of the field. —One symbol of weakness follows after another. The “grass upon the housetops” was, in this respect, a proverbial emblem (Psalms 129:6). The italics in as corn seem to suggest some error in transcription. The words as they stand give a field before the blades; those in 2 Kings 19:26, a blasting.