How would that change have impacted modern-day Christianity?
Part of the impact is ethical. Assume that the church proclaimed a Christ who was, in essence, divine. In that case, how could we talk about following or imitating Christ, if he was not once a man who had shared our weakness and our temptations? If he was just a God visiting earth as a divine tourist, how would we dare ask “What would Jesus do?” We could worship Christ but not try to change the world at his command. And how could we talk of atonement — the core doctrine of Christianity — if Christ had not fully shared our natures? Basic to Christian thought is the belief that we died with Christ, and rise with him. But for that to work, we have to share his nature. The doctrine of Christ’s humanity is also critical for the arts. Now, at various points in their history, both Judaism and Islam have had great traditions of depicting human figures, but often, they have condemned such art as a form of idolatry: you can’t depict God. Christians maintained a sacramental vision by which God
