He bore our sins. Indeed the very history of his family is evidence of his bearing our sin; not just upon the cross but from birth. The following quotation is from The Incarnation of God by Clark & Johnson (A book which has helped me think better about the Savior; worth every page)

many Christians, particularly modern Christians, attempt to isolate, dissociate, and segregate our Lord from sin and sinners at the point of his birth. Yet this is not the aim of Scripture, which instead uses the birth of Christ to identify him with sin and sinners….

On the sordid lineage of our Lord, Thomas Weinandy notes:

Jesus’ ancestors were more than common sinners; they were often a despicable lot. Far from hiding this fact, the Gospel writers appear to glory in it. It was from these ancestors that Jesus took his flesh. He was one of them, and thus he was deeply woven within the defiled but common fabric of man.

Martin Luther focuses on one such ancestor, Judah, to drive this point home:

For it was necessary for [a] lapse to take place in the very line in which the Son of God was to be born. Judah, the very eminent patriarch, a father of Christ, committed [an] unspeakable act of incest in order that Christ might be born from a flesh outstandingly sinful and contaminated by a most disgraceful sin. For he begets twins by an incestuous harlot, his own daughter-in-law, and from this source the line of the Savior is later derived. Here Christ must become a sinner in His flesh, as disgraceful as He ever can become. The flesh of Christ comes forth from an incestuous union; likewise, the flesh of the Virgin, His mother, and of all the descendants of Judah, in such a way that the ineffable plan of God’s mercy may be pointed out, because He assumed the flesh or the human nature from flesh that was contaminated and horribly polluted

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