How were the people of Israel “purchased” per Exodus 15:16?

[Ben Mordecai]

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?

 

[SolaScriptura]

I'd suggest: 1) remember, this is a song, so the language is poetic. In that light, 2) The Lord did mighty works to effect the liberation of Israel. He purchased them by the deconstruction of Egypt and the killing of the firstborn of Egypt. A high purchase price, but one God was willing to pay. 3) In another sense, often overlooked is Ezekiel 20:5-10... which gives a glimpse into how Israel responded to God (through Moses) while in Egypt, and how God's initial response (v8) was... in this light, I cannot help but see the the institution of the Passover as anything other than God making a way for the Israelites not to be killed in the same judgment about to fall upon the Egyptians. So, as Ex 13 makes clear - the first born belong to God. In a very real sense, the Israelites lived because God made provision for the blood of the lambs (prefiguring Christ) to take their place. Thus, in this sense, they were purchased (ransomed) from judgment by God's gracious provision.

 

[Contra_Mundum]

I think Ben has written it true. The price paid was to forego his righteous indignation, to have his justice "take a hit" (as it were) to advantage his love and his promise, mercy triumphing over justice. The death of all the firstborn was an exhibit of the cost, while a portion of that cost was redirected to the substitute sacrifice.

Of course, the fact is that God's wisdom had contrived a way by which sinners deserving wrath might not get what they deserved, and still the justice of God be wholly satisfied. "That he might be both just, and the justifier of him that has faith."

The LORD God "will by no means clear the guilty," and yet also he is "Him that justifies the ungodly." He did, actually, pay an incalculable price for redeeming his people.

 

[Ben Mordecai]

So it sounds like the basic idea is that in the immediate context under a proto-Levitical administration (and later under the actual Levitical administration) there was the shedding of blood as a symbolic atonement which includes the "purchasing" motif. The actual payment for those sins would ultimately paid by Christ, but the participation in the system itself was an exercise of faithful repentance. This would explain why psalms and prophets would say things like "sacrifice you did not require" because they knew the sacrifices were symbolic and the contrite heart, broken spirit, and thankfulness were really what was required.

This being the case, there was the great contrast between the death of the Egyptian firstborn (which would have fallen on Israel had there not been a substitute) and the death of the passover lamb.

Therefore the purchasing of the Israelites could be understood under the scheme that the blood provided them redemption but the Egyptians had no better sacrifice.

Is this line of thinking accurate?