Paul quotes most from Isaiah, The Psalms, Deuteronomy and Genesis. Isaiah is an obvious choice with its large focus on eschatological hope, and also the inclusion of the gentiles. The Psalms would be a good choice as the songbook of the Jews and the early Christians. Deuteronomy’s emphasis on blessings and curses fits neatly into early Christian belief.
The gospel reveals the covenant justice of God.
God has come to put the world to rights.
The good news is about God’s Son, and power is released when Jesus, the Crucified One, Israel’s Messiah, raised from the dead is proclaimed Lord of the World.