I have been struggling with this concept too. I think what I think (that sounds ridiculous) is that the separation from God that sin causes and even death are not in themselves sinful. That our acts of sin cause our separation from God, yet the separation itself is not sin. In this way Christ was separated from God by our sin and redeemed from death and separation according to His being sinless, all of which were possible without Christ being sinful. That the effects of sin are not in themselves sin, and that someone can be in a position of separation from God and still not be sinful.
[sup]John 9:1[/sup]As He passed by, He saw a man blind from birth. [sup]2[/sup]And His disciples asked Him, "[sup](
A)[/sup]Rabbi, who sinned, [sup](
B)[/sup]this man or his [sup](
C)[/sup]parents, that he would be born blind?"
[sup]3[/sup]Jesus answered, "It was neither that this man sinned, nor his parents; but it was so [sup](
D)[/sup]that the works of God might be displayed in him.
Jesus proved that not all of the effects of sin we experience in this life result from sinfulness of the one who experienced the effects or even the parents. Those same words "It was neither that this man sinned, nor his parents; but it was so that the works of God might be displayed in him." can be related to Jesus and His death on the cross. That isn't what this scripture is referring to but I think it is a truth that I think is relevant and true pertaining to Christ and His experience.