"Virtually every line assumes the Old Testament background"
"…analogies are foundational for the theological conclusions that can be drawn from an Old Testament book, and thus fundamental to any Christian reading of the Old Testament. It is commonly said that typology should not be used to formulate doctrine. This claim, popular as it is, is not only wrong; it is preposterous. The whole of New Testament Christology is built on analogies (i.e., typologies) between Jesus and Aaron, Jesus and Moses, Jesus and Melchizedek, Jesus and David, Jesus and Jeremiah, and so on. Even apparently more ”literal” Christological titles and descriptions are fundamentally typo-logical: To say Jesus is Son of Man is to say He is Last Adam; to say He is Son of God is to say (among other things) that He is the Heir to the Davidic throne (2 Sam, 7:14); to say that he is Prince of Peace is to say that He is a new Solomon. No one with a knowledge of the Old Testament can read the gospels and fail to realize that virtually every line assumes the Old Testament background. Even the most “systematic” of New Testament writers, Paul, draws not only theological but ethical conclusions from an avowedly “allegorical” reading of the story of Ishmael and Isaac (Gal. 4:21—3 1) and from a typological summary of Israel’s wilderness experience (1 Cor. 10:1— 10). Far from being illegitimate grounds for theology, typology, I submit, is the only ground for understanding the theological contribution of the Old Testament." -- Peter Leithart, "A Son to Me", pp. 13, 15-16