On City of God in the course of a discussion on the ethics of homosexuality, Matthew made this comment:

“Christ was capable of sin in his humanity but not in his divinity. Therefore, his temptation was real, because he was tempted in his humanity, but not in his divinity. However, Christ was not perfect in his humanity until after the resurrection. Nonetheless, he remained perfect in his divinity throughout his time on earth.”

I thought more about this and disagree. Christ had to have been perfect in His humanity. I came to this conclusion:

Perfection essentially means to be without flaw. Fair enough?

Now, Christ was a sacrifice for sin and we can learn about what was required of Him for this role by examining that which foreshadowed Him — Old Testament sacrifice. Now a lamb chosen for sacrifice had to be blemishless — without flaw, that is, perfect. Since lambs don’t have souls, what had to blemishless was its body. That is, the part of the lamb that could be sacrificed needed to be perfect.

Now, come back to Christ and continue the logic: whatever part of Him that could be sacrificed needed to be perfect. We know that His Divinity was not what sacrificed. It was distressed and removed from the Father, yes, but his Godhood did not die. Of course His body died, however, the component of Christ that was truly crushed for us was the entirety of His humanity. Christ’s humanity was sacrificed. In order for Christ to be a viable sacrifice for sin, the part of Him that could be sacrificed — His humanity — needed to be perfect.

Given His sacrificial role, Christ being perfect prior to crucifixion was far more necessary than for Him to be perfect afterward.

Also consider that Christ is referred to as the second Adam, and we know that Christ did not have a sin nature. Christ’s human life was the result of God’s creation, not human sexual activity — like Adam. So whatever conclusions we come to about Christ’s humanity hold true for Adam’s.