In a recent online forum, the question was broached regarding whether or not Christ was impeccable in the incarnation. The question was raised because R. C. Sproul, a recently deceased theologian, argued that the notion of impeccability, i.e., that Christ was unable to sin, undermines his role as the second Adam who was truly tempted and given the Holy Spirit beyond measure. In essence, if Christ was impeccable, then his obedience to the Father was superfluous because it was already guaranteed. Though I think those who uphold Christ’s impeccability are essentially right, Sproul’s concern brings to the forefront the need to articulate clearly and accurately Christ’s person and work.
The reality is that we have to be ever so careful when articulating the hypostatic union of the Word of God. A slight lapse of wording and one can easily be accused of heresy. The affirmation or denial of Christ’s impassibility is no exception. But, one problem that has to be avoided at the outset is arguing that the person of Christ possesses only one will, namely, the will of God.
Often, those who affirm impeccability, especially on the more popular level, will say such things as “Christ couldn’t sin because his will is the will of his Father and therefore to sin would be to bring division within the Godhead.” This is correct, when speaking from the standpoint of Christ’s divinity. God has one will not three. There is no division or differentiation between the persons of the Trinity, the Son included, regarding the will of God. Or, as I like to put it, the will of God is a threefold will as it is expressed through the three persons of God.
Does Christ possess one will or two? For Christ to be fully human, it would be a prerequisite that he possesses everything a human possesses, which included a will. So, Christ, in his hypostatic union, possesses both the divine will and a human will. To use the divine will as the primary ground for impeccability then is to tend toward Docetism, that is, a denial of Christ’s full humanity. In other words, this move fails to grapple with what those who deny impassibility are getting at, that Christ truly possessed a human will or, to put it more generally, that Christ is fully human.
Now, care is needed here. To emphasize too strongly Christ’s human will tends in the other direction—Nestorianism—unduly dividing Christ’s humanity from his divinity and thus destroying the union of the two natures. So, keeping the proper balance, it must be said that Christ’s possession of two wills does not result in the idea that they are in competition with one another or somehow at odds. There is a unity of the divine and human will in Christ, just as divine and human natures (of which the will is an aspect) are united. The divine and human will are united without mixture, confusion or division. Distinct yet inseparable, as it were.
Yet, as Daley demonstrates in his monograph on patristic Christology, letting the Chalcedonian formula (summarized above) be the exhaustive description of orthodox Christology is to silence the rich and textured voice of the Christian tradition regarding Christ’s person. We will attempt then a more narratival and descriptive account of Christ’s incarnation while keeping in mind the analytical boundaries established by Chalcedon.
Before there was anything, indeed, even the mystery that is creation from nothing (or rather by divine fiat alone), there was the Triune God. One God in three persons where love, joy, beauty, peace, and so many more incredible adjectives could be employed with only a faint glimmer of what they mean. Having created not just one or two things, but the entirety of the created world—the heavens and the earth—God created it good and very good. How incredible and unfathomable that where once there was not, now there was living beings that were distinct from God and yet intimately connected to and dependent on him. Then, the absurd happened. The first humans, made to enjoy a familial, loving relationship with the Triune God, chose the lesser thing, which is really nothing but death. Choosing death in that one fatal, tragic moment, they chose death perpetually.
Death, holding the children of men enslaved to fear, gripped life in all its contours. Hope is evacuated and thus using whatever means to obtain what one wants takes priority. And what follows is that the hearts of men were only violence and evil continually. God brought a temporary solution and eradicated all of life minus a male and female pair of every bird and animal and eight human beings. Yet, this was only temporary as the hearts of men were still gripped by evil and violence, living under the tyranny of death and the fear thereof.
Fast forward, God’s final and perfect solution was to emerge. As the apostle Paul wrote, “when the fullness of time had come” (Gal 4:4) God brought forth the solution to the brokenness, the death-ruled environs of the children of men. He did this by bringing forth his Son. But his Son did not come as a mere apparition, taking on a human appearance but not the reality thereof. Rather, the Son became a human being, assuming a human nature; in every way conceivable, he became fully man. He tasted food, smelled fragrances, and heard sounds. He experienced pain, sorrow, hunger and fatigue. God, yes, truly God, assumed the entire experience of humanity: the emotions, the will, the embodiment of a human being.
God the Son truly obeyed his Father as a human being (can obedience be admitted into the life of the Triune God?) even to the point of death; he obeyed to the point of shedding his blood. Moreover, his obedience was made perfect in his suffering. Obedience then was not some easy, effortless thing for the Son. He endured an existence entirely antithetical to his existence as God. Death was a very real reality as was the temptation to sin.
The entirety of Christ’s life displays in full the depth and significance of Christ’s unwavering trust in, dependence on and obedience to his Father. As fully man, he tasted and felt the sin-filled and death-inundated existence of a fallen creation and yet, seemingly despite all odds, he continued on toward that Rugged Cross. Christ knew better than anyone the power and horror of sin and death because, unlike every other human being, he was truly without sin.
Hence, Satan doesn’t tempt him with trite things like women and pleasure, his tempting words aim at the very heart of who Christ is as God-man and the salvation which was to be wrought by him. “Turn this stone into bread because you’re God after all,” “Throw yourself from this height. I mean, you’re God’s Son, of course he’ll save you,” “Why suffer to receive the kingdom of God and its glory? Just take the easy way out and worship me. No suffering to be had here.” The horror, travesty and tragedy of sin leading to death did not escape God the Son who took on flesh. Indeed, so aware was he of it that his priestly sympathy toward us is unparalleled.
Irenaeus’s construal of Christ’s work as recapitulating the life of the first Adam is repeated and affirmed throughout the fathers both before and after Chalcedon (never mind, Nicaea) and it is this same construal that we are attempting to build on here. Christ, by assuming full humanity, which included obeying God by loving him with his entire being, made possible the salvation of the entire human person. As Falque reminds us, Christ began to taste death as soon as he was born for he assumed a body that was subject to death. By assuming a human nature not in a vacuum nor in an ideal, ‘heavenly’ plane, but in the present reality which is subject to the futility of decay, he made possible the rescue of humanity from its tyranny.
Circling back around to our starting point, impeccability is an understandable and at times necessary short hand. But, as with all short hand or technical terms, their meaning must not be assumed without further ado nor given exhaustive, determinative power over all attempts to articulate Christ’s person and work. Impeccability serves as a boundary for sound affirmations regarding Christ, but if it is made more than this and snuffs out or minimizes the very reality of Christ’s assumption of a human nature in a fallen world and the perfect obedience of Christ in light of this then its defenders have, I would argue, taken the easy way out and removed the substance of the incarnation, reducing in to a thin truism lacking theological weight.
 God Visible (Oxford: 2018).
 This is also the concern of Reformed theologians who affirm the covenant of works and Christ’s ‘active righteousness’ and the corollary of imputed righteousness, albeit with a different grammar.
 God, the Flesh, and the Other (Northwestern University Press, 2014).