God has not casted away His people because of the promises that He made to Israel, as well as what their future would be. Foreknew in the Greek text means “the appointing of a person or people to a certain destiny”

God through His Eternal knowledge decided before creation came into existence, that He would choose a nation to be His representative on Earth, and it would be through this nation that Jesus would come

Paul is stating that God knew what Israel would be before He chose her as a nation. To be predestined does not mean that one is absent of choice, but what it means is that God has determined what an outcome is going to be, and everyone who chooses God’s Way will end up at that predetermined outcome