Did Christ, in his incarnation, assume a fallen human nature? Most Christians I think would answer no to this question. Attempting to preserve the sinlessness of Christ have we gone too far in the other direction? I want to offer two commentary selections on Romans 8:3 and then recommend a book on the subject.
Romans 8:3 reads “For what the law was powerless to do because it was weakened by the flesh, God did by sending his own Son in the likeness of sinful flesh to be a sin offering. And so he condemned sin in the flesh” (NIV) The critical phrase is “likeness of sinful flesh.”
Here’s a selection from C.K. Barrett’s commentary on Romans in the Black’s New Testament Commentary series.
“One possible suggestion is that Paul distinguished between flesh as it was created by God, and ‘flesh of sin’, that is, flesh which had fallen under the dominion of sin. Christ (on this view) had perfect, unfallen flesh, which nevertheless was indistinguishable in appearance from ‘flesh of sin’; he came in flesh, so that the incarnation was perfectly real, but only in the likeness of ‘flesh of sin’, so that he remained sinless.
It is doubtful, however, whether this is what Paul means. The word ‘form’ or llikeness’ (ὁμοίωμα) has already been used several times in the epistle (i. 23; v. 14; vi. 5), and in none of these places does it mean simply ‘imitation’. Compare also Phil. ii. 7, where Paul certainly does not mean to say that Christ only appeared to be a man. We are probably justified therefore in our translation, and in deducing that Christ took precisely the same fallen nature that we ourselves have, and that he remained sinless because he constantly overcame a proclivity to sin. It must be remembered that for Paul flesh (σάρξ) in theological use does not refer to material constituent of human existence but to the manner of human existence as it has, since the entry of sin, come in fact to be. It is the nature of fallen man, living in this world, to be wrapped up in himself. He is conditioned to this kind of existence by the human environment in which he finds himself. Christ found himself in the same human environment as all his fellow men and experienced the same pressures that they feel; yet he remained without sin, living a theocentric existence in an anthropocentric, egocentric, environment. It was in this environment—in the flesh—that sin had to be condemned and defeated if it was to be condemned and defeated at all.” (147)
More recently, consider this passage from Frank Matera’s commentary on Romans in the Paideia Commentary on the New Testament series.
“The precise meaning of the phrase Paul employs here, ‘in the likeness of sinful flesh’ (en homoiōmati sarkos hamaritias), is elusive for two reasons. First, as Florence Morgan Gillman notes (1987, 599), the noun homoiōma could imply ‘similarity but not full identity’ as it does in 1:23; 5:14; 6:5; or ‘full identity’ as it does in Phil. 2:7. Secondly, as Vincent Branick (1985) has argued, sarkos hamaritias can be taken in either an ethical or cosmic sense. Taken in an ethical sense, it suggests that Christ became human to the point of sinning. Taken in a cosmic sense, it means Christ entered into the cosmic situation of sin and death that afflicted Adam’s descendents. Given Paul’s insistence on Jesus humanity (Rom. 1:3; Gal. 4:4), it is unlikely that Paul employs ‘likeness’ in the sense of similarity but not full identity. And since Paul has already spoken of sin and death as cosmic forces and affirms Christ’s sinlessness in 2 Cor. 5:21, the phrase ‘sinful humanity’ is best taken as a description of the cosmic condition into which Christ entered rather than his sinfulness. In a word, Paul affirms that the preexistent Son, whom the Father ‘sent’ into the world, possessed the very ‘form,’ ‘image,’ and ‘likeness’ that defines the human condition. Accordingly, the Son entered the realm of sinful flesh—a realm determined by the cosmic powers of sin and death—as one totally human, but not a sinner. For had the Son of God sinned, he would have been no different than those whom he came to redeem. Instead of defeating sin in the realm of sinful flesh, he would have been defeated by sin.” (192)
One of the best treatments on this topic which answers our question in the affirmative is In the Likeness of Sinful Flesh by Thomas Weinandy. He writes:
“While Christian theologians have stressed that the Son of God became like us in every way, what they have almost universally neglected and ignored, both in the present and the past, is that in the Incarnation, the Son took upon himself, not some generic humanity, but our own sinful humanity. While he never sinned personally, or, as we will see, had an inner propensity to sin (concupiscence), nonetheless his humanity was of the race of Adam and he experienced, of necessity, many of the effects of sin which permeate the world and plague human beings—hunger and thirst, sickness and sorrow, temptation and harassment by Satan, being hated and despised, fear and loneliness, even death and separation from God. The eternal Son of God functioned within the confines of a humanity altered by sin and the Fall. ‘He was both God and the son of Eve.’ This then is what we mean, when throughout this study, we speak of ‘Jesus’ sinful humanity,’ his ‘sinful flesh,’ or his ‘sinful human nature.’” (17-18)
Weinandy treats the subject historically (finding it affirmed by Thomas Aquinas, Karl Barth, and Edward Irving [who was condemned for espousing the doctrine] among others), Biblically and theologically. It is a minority position but one that ought to be considered more carefully.