Genesis 15 and 17

Do Genesis 15 and 17 constitute two related but distinct Abrahamic covenants?

Yes

Paul R. Williamson, in his very helpful and thorough NSBT volume Sealed with an Oath argues that Genesis 15 and 17 constitute separate (though obviously related) covenants. Here are his reasons as best I can distill them:

1. Gen 15 is unilateral; Gen 17 is bilateral (“be blameless, so that”).
2. Gen 15 has no covenant sign; Gen 17 has circumcision.
3. Gen 15 mentions no international dimensions or royal descendants; Gen 17 does.
4. Gen 15:13-16 gives an explicit timetable for when God’s promises will be fulfilled–after they go through 400 years of slavery; Gen 17 says that God’s covenant will be established, implying that it has not been already established (in Gen 15).
5. Gen 15 says nothing about what God will do with that nation after it is established; Gen 17 speaks of God’s covenant with Abraham’s descendants as “everlasting.”

Williamson offers this summary statement:

It is clear from the above analysis that the covenants mentioned in Genesis 15 and Genesis 17 are manifestly different in both nature (temporal/eternal; unilateral/bilateral) and primary emphases (national/international). The suggestion that they are simply two stages of the one covenant is seriously undermined by the inexplicable gap of some thirteen years between them, and by the consistent projection of the covenant in Genesis 17 into the future (lit. ‘I will give my covenant’ [Gen. 17:2]; ‘I will establish my covenant” [Gen. 17:7 my trans.]). Both these anomalies, as well as the significant differences between the two covenant chapters, suggest a more plausible synchronic explanation: these chapters focus on two distinct, but related covenants. (p. 89)

No

But… The Old Testament itself treats all the various promises to Abraham—and Isaac and Jacob—as one covenant (Ex 2:24; 2 Kgs 13:23; Lev 26:42 need not be speaking of three separate covenants, and in any case, it ascribes only one covenant to Abraham.) The Bible, in fact, never speaks of more than one covenant with Abraham (cf. Acts 3:25). If the two are related but distinct, the relation must be a lot more prominent than the distinction.

Mathews (NAC) points out that “the apostle Paul treats the covenant chapters in Genesis as one covenant when he contends on the basis of the life of Abraham that salvation is received by faith alone (Rom 4:1–25).” In that chapter, in fact, quotations from Gen 15 and Gen 17 are treated as part of the one promise of God to Abraham; both chapters are quoted with no intimation that they come from different covenants. The one fact of importance Paul draws out of the distinction between chapters 15 and 17 is that Abraham’s faith was credited to him as righteousness (ch. 15) before he participated in the sign of circumcision (ch. 17). So to Paul, the stages of the Abrahamic covenant are significant because they make faith logically prior to works in the ordo salutis.

And lest we use that point to push Genesis 15 and 17 apart again—one is unilateral and therefore gracious, the other is bilateral and therefore works-based—James unites the two poles and uses Abraham as his example in doing so (Jas 2:14–26). Abraham’s works vindicated his (logically prior) faith, showing it to be really real.

I think Williamson (in an otherwise very helpful book!) makes too much of the distinctions between Gen 15 and 17. I admit I’m not sure what to do with the tense distinctions—and Williamson surely did some careful, challenging exegesis. But I do wonder if he should have violated (?) biblical-theological methodology just a bit and let Paul do some authoritative apostolic exegesis for him.