I really appreciated these comments from Karl Barth’s Christ and Adam: Man and Humanity in Romans 5 (trans. Wilhelm Pauck) on the provisional humanity of Adam that foreshadows the fulfilled humanity of Christ:
“The first man is of the earth, earthy, the second man is from heaven.” That is how Paul puts it in 1 Cor. 15.47. Christ is above, Adam is beneath. Adam is true man only because he is below and not above, because his claim to be the “first man” and the head of humanity like Christ is only apparent. We are truly men because we, like Adam, are below and not above, because Adam’s claim to be our head and to make us members of his body are only apparent. We are real men in our relationship to Adam, only because Adam is not our head and we are not his members, because above Adam and before Adam is Christ. Our relationship to Christ has an essential priority and superiority over our relationship to Adam. He is the Victor and we in Him are those who are awaiting the victory. Our human nature is preserved by sharing Adam’s nature, because Adam’s humanity is a provisional copy of the real humanity that is in Christ. And so as Adam’s children and heirs, in our past as weak, sinners, godless, and enemies, we are in this provisional way still men whose nature reflects the true human nature of Christ. And so, because of our nature in Christ, its formal structure can and must even in its perversion be the same. (pp. 46-47)
In other words we must not mourn our Adamic humanity even though it only foreshadows real human existence. Our Adamic humanity is “the stuff” from which our Christianized humanity is made. This is a long way of saying be thankful even for your horrid Adamic humanity because it is from this that we can become what humans have always aimed to become–that which Christ already is.