God made Himself small for us
The Christ had to suffer and die, because whenever the Divine appears in all its depth, It cannot be endured by men. It must be pushed away by the political powers, the religious authorities, and the bearers of cultural tradition. In the picture of the Crucified, we look at the rejection of the Divine by humanity. We see that, in this rejection, not the lowest, but the highest representatives of mankind are judged. Whenever the Divine appears, It is a radical attack on everything that is good in man, and therefore man must repel It, must push It away, must crucify It. Whenever the Divine manifests Itself as the new reality, It must be rejected by the representatives of the old reality. For the Divine does not complete the human; It revolts against the human. Because of that, the human must defend itself against It, must reject It, and must try to destroy It.
Yet when the Divine is rejected, It takes the rejection upon Itself. It accepts our crucifixion, our pushing away, the defence of ourselves against It. It accepts our refusal to accept, and thus conquers us. That is the centre of the mystery of the Christ. Let us try to imagine a Christ Who would not die, and Who would come in glory to impose upon us His power, His wisdom, His morality, and His piety. He would be able to break our resistance by His strength, by His wonderful government, by His infallible wisdom, and by His irresistible perfection. But He would not be able to win our hearts. He would bring a new law, and would impose it upon u by His all-powerful and all-perfect Personality. His power would break our freedom; His glory would overwhelm us like a burning, blinding sun; our very humanity would be swallowed in His Divinity. One of Luther’s most profound insights was that God made Himself small for us in Christ. In so doing, He left us our freedom and our humanity. He showed us His Heart, so that our hearts could be one. — Paul Tillich, “He Who Is The Christ,” The Shaking of the Foundations, pp. 147-8.