One of the most significant divisions among Protestant Christian groups is the lens through which they view the overarching narrative of the Bible and the pursuit of God to make for himself a people. It is clear that, in the Old Testament, God chooses a family through which to work His plan of redemption. Through many twists and turns, this family becomes the Hebrew people, Israel. Out of this family arises the Messiah, Jesus Christ. Through His life, death, resurrection, and ascension the offer of eternal life is extended to all people, not just the Hebrews. To this, all Christians agree.
The difference comes in how we see the relationship between what God did before Christ through the Hebrew people and what He does after and through Christ for all people. There is a spectrum of positions on this question, but the broadest generalization of the perspectives falls into two main categories: dispensationalism and covenentalism.