In the triumphal song of Moses, it is mentioned in 15:15 that the people were purchased. Exodus 15:16 Terror and dread fall upon them; because of the greatness of your arm, they are still as a stone, till your people, O LORD, pass by, till the people pass by whom you have purchased. (ESV) "Purchase" usually implies an exchange of one valuable thing for another valuable thing. Purchasing language becomes important in the New Testament for understanding the sense that the Lord Jesus purchased his people with his own blood. In the Exodus, there is no clear exchange taking place. The Exodus appears mainly to be a triumph of the Lord against his enemies. Yet Moses sings of a purchase. How does Reformed covenant theology understand the purchase here described? Is this a foreshadowing of the ultimate purchase of God's people with the blood of Christ, or is there a more immediate sense that a purchase has taken place?