Albert Barnes Commentary Isaiah 10:19

"And the remnant of the trees of his forest shall be few, so that a child may write them." — Isaiah 10:19 (ASV)

And the rest of the trees ... - Still keeping up the image of a large and once dense forest, to which he had likened the Assyrian army. ‘The rest’ here means what will be left after the threatened judgment comes upon them.

That a child may write them - That a child will be able to number them, or write their names; that is, they will be very few. A child can number or count only a few; yet the number of those who would be left would be so very small that even a child could count them with ease. It is probable that a few of the army of Sennacherib escaped (see the note at Isaiah 37:37); and compared with the whole army, the remnant might bear a striking resemblance to the few decaying trees of a once magnificent forest of cedars.