I am getting tired of people using Genesis 12:2-3 as a "support Israel" club. God spoke these words to Abraham as he's leaving his home forever. They are meant to be an encouragement to him, not an order to everyone else. Ignoring these words led to problems for Abraham in Egypt and other places, where instead of trusting God, he lied to the leaders about his relationship with Sarah. He didn't give them a chance to bless him or allow God to curse them if they did wrong to Abraham.
The question is how does this personal encouragement apply to us and the nation of Israel? It's a huge hermanuetical stretch to say that it had the post-Temple world in mind. Being aligned with God's faithful is the interpretive key concept, not some ethic group. Even today, every evangelical Christian will wholeheartedly admit that the entire nation of Israel is utterly rejecting God, starting with the Zionist athiest Benjamin Netanyahu himself. Love them if you want, but we are told by Paul to not be unequally yoked.