Charles Ellicott Commentary Isaiah 48:19

"thy seed also had been as the sand, and the offspring of thy bowels like the grains thereof: his name would not be cut off nor destroyed from before me." — Isaiah 48:19 (ASV)

Like the gravel thereof. —Literally, as its bowels, that is, as that within the bowels of the sand, the living creatures that swarm in countless myriads in the sea. The two verses utter the sigh which has come from the heart of all true teachers as they contemplate the actual state of people and compare it with what might have been. (Luke 19:42.)