Why did God set Israel apart as a nation in the Old Testament?
God set Israel apart as a nation to give them the Law and the Temple, and to use them as a channel to bring the knowledge of the God of Abraham, Isaac, and Jacob back to the ungodly river of humanity. This was His sovereign plan, but Israel's unbelief prevented it from working.
Les explains that from Genesis chapter 12 and the Abrahamic Covenant, God dealt with the nation of Israel, giving them the Law and the Temple. The idea was that one day God would funnel them back into that filthy, ungodly river of humanity to bring them a knowledge of the God of Abraham, Isaac, and Jacob. Les teaches that this was the noble plan of God in His sovereignty, but it did not work because Israel did not believe it. In time, Moses gave Israel the Law around 1500 B.C., and later David and Solomon appeared around 1000 B.C., with Solomon building the first Temple, which stood about 350-400 years.