Question: "What is Old Testament theology?"
Answer: Old Testament theology is the study of what God has revealed about Himself in the Old Testament. The system of Old Testament theology takes the various truths that the Old Testament books teach us about God and presents them in an organized fashion. God's revelation of Himself begins in Genesis 1:1: "In the beginning God created the heavens and the earth." The presupposition of God and His creative work is something that all believers accept by faith and is emphasized throughout Scripture from Genesis to Revelation.
Old Testament theology is a rich and rewarding study of what God revealed of Himself, His character, His attributes, etc., in the Old Testament. The Old Testament focuses primarily on God's relationship with the Jews, starting with His call of Abraham in Genesis 12. He chose Israel and covenanted with them for the purpose of relaying His message to the world and ultimately bringing the Messiah to save us from our sin. Through His relationship with the Jews, God blessed the entire world (Genesis 12:3). The Old Testament chronicles God's progressive revelation of Himself, specifically to His chosen people but also to those of Gentile heritage, in order that we might learn who He is and His plan in the world. Into the very heart of the Old Testament is woven the idea of a covenant between God and man: the first was made with Adam and others with Noah, Abraham, the nation of Israel, and David.
Old Testament theology is foundational to our understanding of God and His purposes in the world. The seeds of the doctrines of substitutionary atonement, salvation, election, holiness, mercy, judgment, and forgiveness are all found in the Old Testament. A study of Old Testament theology includes a look at theology proper, anthropology, and eschatology, among other vital subjects.