Why is it hard to understand that Israel rejected God after He supernaturally made them a nation?
It is hard to understand because God supernaturally formed Israel, called Abraham, fulfilled the promised son Isaac, multiplied Jacob's sons, and brought the nation out of Egypt by miracle after miracle, yet Scripture describes them as disobedient and gainsaying, resisting God's outstretched hands all day long.
Les explains that this is one of the toughest things in Scripture for him to comprehend. God supernaturally brought the nation of Israel into being: He called Abraham out of Ur of the Chaldees, promised to make him a nation, fulfilled that promise through the supernatural birth of Isaac, and through Isaac, Jacob, and the twelve sons the people ended up in Egypt. There God began dealing with them as His chosen, set-apart nation, and He brought them out supernaturally with miracle after miracle, with the multitude following Moses. Yet Romans 10:21 says God stretched forth His hands all day long to a disobedient and gainsaying people. The same pattern appears with Peter and the other believers: they did not recognize the Messiah by their own smarts; the Father had to open their understanding. The difficulty is the contrast between such supernatural dealings and Israel's continued disobedience and resistance.
But to Israel he saith, All day long I have stretched forth my hands unto a disobedient and gainsaying people.