Because the 2nd person of the Trinity existed before the creation of the earth. (Yeah I know, I just offended a heap of peeps) His eternal purpose was always to become incarnate. Christ, was always God’s plan to redeem his people. Christ was, is and will always be the elect. Israel as a nation, was elected to bear forth Christ. Their election by God, was always within the framework of bearing forth Christ. God’s eternal plan for the salvation of all humanity.
The incarnation was never plan B. Instead, before the creation of the world. God planned to redeem and reconcile humanity to himself. The elect of God, Christ, died our death, so that we might live. We live; not through his death; instead we live through his life. Through his death we gain forgiveness of sin. Through resurrected life, we are justified. He ascended to God the Father. The scars of the cross remain etched into his body for eternity: an intercession for us, scars that pave the way to God; only for those who would follow.
For its those who would receive him, he receives in Himself. Though he died for all; its only those who follow him, he lives for. For life can only be granted to those who follow him. For he is the way, the truth and the life. For whoever believes in him, shall not perish; but receive eternal life. But for those who don’t receive him. For those who don’t believe, receive and follow, there is no resurrected life.