I thought this presentation by Demetrios Bathrellos was apropos given the recent posting and interchange by Darren and Oliver Crisp here and here on the issue of Christ’s sinlessness or “impecabbility.” I once wrote a paper on this during my school days, and came to the same conclusion that Bathrellos and Crisp have (the “traditioned” one). The following is going to be a lenghthy quote provided by Bathrellos (don’t let the fact that Bathrellos is Eastern Orthodox shy you away from his cogent points on this subject), I think his material approach really undercuts the posse non peccare (“able not to sin” [but could’ve]) that some folks seem to want to hold for Jesus in regards to the temptations that he faced while in His kenotic state — the fear is, is if Jesus wasn’t completely embodying a fully human state (read “fallen state” or nature); then he couldn’t fully save us (following the Gregory of Nanzianzus dictum: “the unassumed is the unhealed” — which by the way I agree with, but only qualified in the way that Bathrellos provides). Here is Bathrellos:
Sometimes the objection is raised that the position that the human nature of Christ was sinless is at odds with Chalcedonian Christology. According to the logic of the objection, Chalcedon pointed to the fact that Christ should be as truly and fully human as we are, and this, so the objection goes, inevitably entails that he must have borne a sinful human nature as we all do.
This objection arises from a theologically valuable sensitivity to avoid any latent Christological docetism that would remove Christ from our human condition and thus run the danger of eliminating any relevance that his human life and death may have had for us. But the objection attempts to avoid this danger in the wrong way.
In fact, there are three problems with it. First, it is historically mistaken. The Council of Chalcedon had nothing to do with justifying the view that Christ bore a sinful humanity. On the contrary, its definition makes it clear that Christ did not assume our sinfulness.
Second, the objection turns Christ into a sinner. As Oliver Crisp has justifiably argued, to say that Christ has a fallen nature means that he also bears original sin and is sinful, which is fatal to the argument. Indeed, to turn Christ into a sinner is a cost that Christian theology cannot afford [T. F. Torrance agrees, see hyper-link].
Third, the objection implies a false understanding of human nature. Sin is not a defining charcteristic of human nature. If this were the case, only sinners would be real human beings —- Adam before the fall, or the saints in the eschatological kingdom, would not be. If being a real man means being a sinner, then given the relational understanding of sin outlined above, alienation from God and authentic humanity would be coterminous. However, this is not a tenable theological position, but a worn-out claim of modernity.
In fact, we would go so far as to reverse the above-mentioned claim and say that authentic humanity is humanity in God. Humanity cannot be thought of as something complete and self-contained prior to and independently of God —- let alone against him. Unity with God is a defining characteristic of authentic humanity, without which the latter is not what it really is. This is why sin, which consists exactly in alienation from and in opposition to God, does not make us more but less human. Sin is a privation that distorts and minimizes our humanity. Christ was fully and authentically human, not in spite of the fact that his humanity was sinless, but because of it. Christ was not a sinner. What he assumed, he sanctified and redeemed. He redeemed our nature, not our sinfulness. In him, we are justified, not our sin. [brackets and emboldening mine] (Paul Metzger, ed., Demetrios Bathrellos, “Trinitarian Soundings in Systematic Theology,” 116-17)
It is my position that Christ truly did assume “sinful humanity” in His incarnation, but He immediately and eschatologically sanctified this humanity, in His ‘humanity,’ by the Spirit; so that while He was “limited” by the effects of the Fall (e.g. hunger, thirst, sickness, etc.), He never participated in the principle of the Fall (i.e. a ‘fallen nature’). In this sense then, it can be said that Christ ‘assumed sinful humanity, and thus healed it,’ but in a way that non posse peccare (“not able to sin”) is retained. I think the key point of Bathrellos’ offering is his differentiation between being human, and sinful; the former does not require the latter —- but the latter certainly requires the former. Which means that to be truly human is to be rightly related to God, which is an always already reality for Christ within the ontological and thus economic relations of God’s life for us.
So to say that Christ needed to be able to sin — if not He didn’t really become human — is to misunderstand the Incarnation in adoptionistic kind of ways!