Albert Barnes Commentary Isaiah 28:13

"Therefore shall the word of Jehovah be unto them precept upon precept, precept upon precept; line upon line, line upon line; here a little, there a little; that they may go, and fall backward, and be broken, and snared, and taken." — Isaiah 28:13 (ASV)

But the word of the Lord was unto them - Or, rather, the word of Yahweh "shall be" to them. This refers to the way God said He would instruct them in a foreign land.

They had complained (Isaiah 28:9–10) that his instructions had been like a short lesson constantly repeated, as we instruct children. God here says that it would be just as they had described: they would be carried away to a distant land and live for a long time among strangers.

There, they would have ample time to receive instruction. And all they would receive would be lesson after lesson of the same kind—line upon line, one judgment following another—until the lesson of their disobedience had been fully instilled in them, and they were brought to true repentance.

Here a little, and there a little - This is how they had described God's lessons given to them by the prophets (Isaiah 28:10). So God says his lessons "shall be" to them through judgment. It would not come in one sudden and overpowering burst of indignation, but it would be, so to speak, dealt out to them in small portions so that it would not be quickly exhausted.

That they might go ... - This was so that they would go into captivity, and stumble, and be broken by the judgments of God. God would deal out the lessons of his judgment and wrath in such a way that, as a people, they would be broken up, made prisoners, and carried to a distant land.