Every Christian heresy and every Christian error is rooted in diminishing Christ's deity
We cannot diminish that Christ is fully God and fully man.
When he became man, his humanity did not add or take away from his deity.
But his deity means everything for humanity! His deity means that we can grow in godliness and one day we can be perfected.
Christ had to become fully human in order to fully redeem those who come to him.
In Christ, we are being redeemed and will one day be fully redeemed bodily, and in mind and soul.