What does Isaiah 10:22 mean?
It's possible some Israelites in Isaiah's day held the same attitude as some religious leaders who talked to Jesus. They took God's promises to Abraham that their numbers would be as "countless as the sands of the sea" (Genesis 22:17) to mean that the Lord would never judge them for their sinfulness.Jesus directly confronted this false idea. Speaking of judgment to come on Israel, "Do not begin to say to yourselves, 'We have Abraham as our father.' For I tell you, God is able from these stones to raise up children for Abraham. Even now the axe is laid to the root of the trees. Every tree therefore that does not bear good fruit is cut down and thrown into the fire" (Luke 3:8–9).
Isaiah, too, directly disagrees that God's promise means that God cannot decrease the number of Israelites for a time. Only a remnant will remain after the failed siege of Jerusalem by the Assyrians (2 Kings 19:35) and much later after the captivity in Babylon.
Paul quotes this verse in Romans 9:27–28, speaking of the remnant of Israel that will be eternally saved through faith in Christ. Isaiah concludes by saying that God's judgment in this destruction is filled with righteousness. In other words, the Lord is right and acting fairly in only leaving a fraction of the people of Israel due their faithlessness and disobedience.