St Gregory’s letter to Cledonius (101) has one of the most important and famous Patristic statements (present in other forms in other Fathers as well): “Or, for that which is not taken up (or assumed) is not healed.
That which is united to God, that will be saved.If half of Adam fell, also half will be taken up and saved. But if all [of Adam], all of his nature will be united [to God], and all of it will be saved.”
Why does this matter? Why does Christology matter? Because God has come to us to redeem, to save, to heal, the entirety of us; that gives us the power and responsibilitiy to live entirely new lives, body and soul, by the power of the Spirit, in holiness for eternal life. He has done it for us, and calls us to join him.