A great quote from T. F. Torrance in his article, "The Hypostatic Union" (36, paragraphing mine) —
It is important to see that if the Deity of Christ is denied, then the Cross becomes a terrible monstrosity.
If Jesus Christ is man only and not also God, then we lose faith in God and man.
We lose faith in God because we could not believe in a God who allows the best man that ever lived to be hounded to death on the Cross—is that all that God cares about our humanity and its search after God, after truth and righteousness and peace?
Put Jesus Christ a man on the Cross, and put God in heaven, like some Mohammedan deity imprisoned in His own lonely abstract Deity—and you cannot …