Often, when we talk about the Old Testament, we talk about God's promises and work for his chosen people, Israel. We talk about God's redeeming promise to Adam and Eve. God calls Abraham out of the Haran into Canaan. God sends Moses to Pharaoh with a message of liberation. God sends Samuel to anoint David. God speaks through his prophets, and so on. Often, when we talk about the Old Testament, we talk about "God" generically. But, what about the Trinity? What about the Son? Is the God of the Old Testament different than the God of the New Testament?
Early New Testament writers think so. Jude says that the Lord (Jesus) led Israel out of Egypt and punished their disobedience (Jude 5). Paul says Christ was with Israel in the wilderness (1Cor. 10:1-10). John says Isaiah saw the Son in his call vision (John 12:41). Jesus himself says that as the Son he interacted with Abraham (John 8:56-59). So where did we get the idea that the Son never shows up in person in the Old Testament?
From the heretic Marcion to St. Augustine, early Christians taught that the God of the Old Testament shouldn't be confused with the God of the New Testament as he's revealed and worshipped in Jesus the Christ. This was both a popular teaching and a debated question for centuries before Martin Luther - an Old Testament professor at the University of Wittenberg - argued and popularized the opposite:
Thus it follows powerfully and irrefutably that the God who led the people of Israel out of Egypt and through the Red Sea, who guided them in the wilderness through the pillars of cloud and fire, who nourished them with heavenly bread, and who performed all the miracles Moses describes in his book, who also brought them into the land of Canaan and then gave them kings and priests and everything, is therefore God and none other than Jesus of Nazareth, the Son of the Virgin Mary, whom we call Christ our God and Lord... And, again, it is he who gave Moses the Ten Commandments on Mount Sinai, saying, "I am the Lord your God who led you out of Egypt; you shall have no other gods." Yes, Jesus of Nazareth, who died for us on the cross, is the God who says in the First Commandment, "I, the Lord, am your God" (Last Words of David, Luther's Works, 313-14).
What Luther picks up on, and others who follow him, is that the New Testament is a "commentary" on the Scriptures. The New Testament is the key that unlocks the Old. It's not that we need the New Testament authors to teach us how to read the Scriptures. They teach us that unless we see the Son everywhere present for his people, from Genesis to Malachi, we don't understand the Scriptures at all!
Jesus doesn't just point to YHWH, he is YHWH: "You search the Scriptures;... it is they that bear witness to me... Do not think that I shall accuse you to the Father; it is Moses who accuses you, on whom you set your hope. If you believed Moses, you would believe me, for he wrote of me. But if you do not believe his writings, how will you believe my words?" (John 5:39,4547).
And, "And beginning with Moses and all the prophets, he interpreted to them in all the Scriptures the things concerning himseIf" (Luke 24:17).
The Angel of the LORD, who bears the name YHWH, is Jesus. As he says, "Behold, I send an angel in front of you, to guard you on the way and to bring you to the place that I have prepared. Be attentive to him and listen to his voice; do not rebel against for he will not pardon your transgression; for my Name is in him. But if you listen to his voice and do all that 1say, then I will be an enemy to your enemies and an adversary to your adversaries" (Ex. 2320-22).
The "Angel" bears God's Name and can retain and forgive sins, which belongs to YHWH alone.
Paul says in 1 Corinthians 10 that the glory of YHWH - the cloud, the fire, the man-like presence on the throne - is Jesus. The Word of YHWH, is Jesus. The Son was with Israel as they traveled through the wilderness after the exodus from Egypt. Paul also points out for us that the Wisdom of God is Jesus too (1 Corinthians 1:24; 2:7).
The Name of YHWH, which cannot be separated from the person of God, is the Son, Jesus. As John writes: "But to all who received him, who believe in his Name..." (John 1:12). And later, "Holy Father, protect them in your Name that you have given to me, so that they be one, as we are one. While I was with them, I protected them in your Name that you have given to me" (John 17:11b).
Finally, the Word of God, as John writes at the beginning of his Gospel, is Jesus. At the end we also read about God's Word that: "His eyes are like blazing fire, and on his head are many crowns. He has a name written on him that no one but he himself knows. He is dressed in a robe dipped in blood and the name by which he is called is the Word of God" (Rev. 19:12-13).
When we read the Old Testament, we don't have to look only for prophecies about the Christ, or types of Christ as they show up in the persons of Joseph, Samson, and others. Instead, what the New Testament authors reveal to us is that unless we recognize that the Son is physically and orally present for his people from the beginning, we fail to understand anything in the Scriptures. The entire Scriptures reveal Jesus, the Son, the world's Savior, to us.
The importance of this for Christians was summed up by a professor when he said: "The Son's words and deeds in the Old Testament climax in the incarnate Son, who was crucified, died, and rose again on the third day. Jesus not only revealed YHWH to be Father, Son, and Holy Spirit, but he gave the ultimate revelation of who YHWH truly is by mounting the cross and giving his life for the life of the world. Moreover, it is vital to help others see that this Son is still present with his church, bringing the salvation won at the cross to us through his washing, speaking, and feeding in the church today" (Charles A. Gieschen, The Real Presence of the Son Before Christ: Revisiting an Old Approach to Old Testament Christology).
The Old Testament doesn't Only tell us about the Christ that is to come... All Scripture is pure Christ. Amen.