Is Jesus a propitiation?

He is the propitiation for our sins (1 Jn 2:2).

whom God put forward as a propitiation by his blood, to be received by faith (Rom 3:25).

1. "Propitiation" is the traditional rendering. But is that correct? An alternative rendering is "expiation". The typical distinction is that one expiates sin while one propitiates an agent. Propitiation is more personal while expiation is more impersonal. 

2. Roughly two sources form the possible background:

i) Cultic usage involving Yom Kippur. Sacrificial blood in relation to the inner sanctum.

ii) Extrabiblical usage in which a ritual is used to appease an angry deity or vengeful spirit. 

3. An objection to (i) is that Paul doesn't typically make explicit and extensive use of the Mosaic cultus, unlike Hebrews. 

i) Yet as a rabbi steeped in the OT, that would be a subliminal presupposition for much of his theology.

ii) It may also be that he doesn't usually employ those categories because so much of what he writes is addressed to gentiles. Yet it would always be in the back of his mind, within easy reach. 

iii) In addition to that, Paul may well be suggesting that Jesus replaces the OT sacrificial system. A type/antitype relation.

4. Another objection to the cultic sense is that produces a jumbled image of Christ as priest, victim, and mercy-seat all rolled into one. That, however, fails to distinguish between conceptual consistency and figurative consistency. The Bible uses picture language (concrete metaphors, enacted parables) to illustrate different facets of redemption. Sometimes that produces mixed metaphors. But picturesque metaphors needn't be realistic. 

5. An objection to "propitiation" is that it casts God in the role of a petty, vindictive heathen deity. 

i) That's not an exegetical objection. Rather, that's based on a preconceived notion of what is fitting for God.

ii) One crucial difference between the Biblical/Pauline conception and the pagan conception is that in the pagan notion of propitiation, humans take the initiative to pacify an angry god or spirit. The losing side has an incentive to broker a truce, while the winning side has no such incentive. 

Moreover, their rituals sometimes have the power to manipulate vindictive gods or vengeful spirits. 

By contrast, the biblical God takes the initiative to resolve hostilities. That reflects divine condescension and clemency. Normally, it's up to the offending party to seek reconciliation with the offended party. But because sinners are unable and unwilling to take the initiative in that regard, the offended party (God) initiates reconciliation with the offending party (sinners). Sinners don't propitiate God. Rather, the Redeemer takes that action. 

And God can't be arm-twisted. He's the one who set up the sacrificial system in the first place. 

iii) I think it likely that Paul is trading on both associations. In Romans as well as the Pauline corpus generally, you have the theme of God's wrath. That, of course, has an OT background, as well as an eschatological dimension. But "propitiation" would also resonant with a gentile audience by intersecting with shared connotations. 

At the same time, Paul has a foot in the OT. And he wishes to show that Jesus fulfills the OT. The mercy-seat was a placeholder. The cross supersedes the mercy-seat.  

6. If we confine ourselves to the Fourth Gospel and 1 John, Johannine theology lacks the same sustained, explicit emphasis on God's wrath that we find in Paul, although that's touched on in a few passages (e.g. Jn 3:36). Of course, if we include Revelation in the Johannine corpus, then divine wrath looms large.

However, I think the notion of divine wrath is somewhat anthropomorphic. It's not that God actually loses his temper. Rather, I think divine "wrath" is a colorful way to express divine judgment against injustice. And the whole point of atonement in the Fourth Gospel and 1 John is to avert eschatological judgment for Christians. So in that more abstract sense, "propitiation" has a place, although a more generic term might be preferable. 

This also resolves the tension of the Son placating the Father. That's not the level at which the transaction operates. Rather, it concerns the satisfaction of divine justice. 

7. 1 Jn 2:2 may be an alternate formulation to express the same idea conveyed in 1:7: "The blood of Jesus his Son cleanses us from all sin".