Why Christ suffered.
I. The answer to this question is very simple. He suffered as a sacrifice for the sin of the world. It was the ultimate and perfecting act of His obedience, to carry down into death that death-sentenced nature which He had taken into the Godhead; to subject His Divine Person to the dark and to us utterly mysterious contact with the actuality of death; and to put by His almighty power of casting off from Himself the sentence of death which He bore about Him. This is why Christ died; that He might in His own Body, as the Second Head and including Representative of mankind, pay the penalty of death which rested on that manhood which was summed up in Him. The Godhead of our blessed Lord is an element absolutely necessary to the belief of even the least portion of the benefits and effects of His death. If a man do not firmly and clearly hold that, he has not a notion of what is meant by the doctrine of Christ's atonement for sin. His entire oneness with the Father lies at the very root of all.
II. I proceed to our second enquiry. Granted, that it was necessary for Christ to submit to death in order to the taking away of the sin of the world, why did He die as He did?First I say in answer, that we cannot tell how much of deep humiliation and desertion and anguish was absolutely necessary, in the covenant which infinite wisdom arranged, to make that death the full and sufficient sacrifice, oblation and satisfaction, for the sins of the whole world. The analogy of the Redeemer's whole life leads us to the humble inference that nothing less than such an amount of self-denial, and endurance of pain, and contradiction of sinners, was enough for the accomplishment of His mighty purpose, even in its hidden and unfathomable recesses, where it flowed forth from unity with the Father's will. (2) But if we look at this same matter from another and a human point of view, even to usthere may be made plain and full and sufficient reason why these sufferings should have been undertaken. Our blessed Lord sums it up for us in a few simple words "I, if I be lifted up, will draw all men unto Me." These stupendous sufferings of the Son of God were undertaken to put away sin; the sin of the world; the sin of each man; and they were undertaken that each man might be mightily constrained by the power of the Divine love shown in them, to take up the freedom thus purchased for him; to see himself complete in Christ his satisfaction before God; to live as Christ's freeman, prevailing over and conquering sin, and daily renewed with God.
H. Alford, Sermons on Christian Doctrine,p. 166.