What does Isaiah say will happen to Israel even if their number is as the sand of the sea?

Les teaches that in Romans 9:27 Paul goes to Isaiah, where Isaiah cries concerning Israel: 'though the number of the children of Israel be as the sand of the sea, a remnant shall be saved.' Les stresses what he calls the doctrine of the remnant. All through Scripture, God has never enjoyed the majority; it has always been that small remnant. Les illustrates this with the flood: out of all the billions of people on the earth at that time, only eight remained true to God, a little tiny remnant, even though some of them later became rather despicable. Then when the nation of Israel comes into view, the Word would light on Jacob, the whole nation, but only a few out of Jacob would respond and believe, and they were usually referred to as Israel. Les says it is the same way here from Isaiah: God has always had His remnant, even within the nation of Israel.