Chizuk Emunah (Pt 2) Under the Microscope: Chapter 24

Matthew 26:39, "And he (Jesus) went a little further and fell on his face, and prayed, saying, O, my Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as thou wilt." See likewise Mark 14:35, and Luke 22:41. This passage refutes the Christian belief, that Jesus offered himself spontaneously as the sacrifice for the salvation of mankind. If that had been the case, why should he have hesitated and prayed for the removal of the bitter cup of his portion; and why should he have exclaimed. "My God, my God, why hast Thou forsaken me"! (see Matthew 27:46). This is another proof that the Father and the Son are not identical, and that the design of the one does not accord with that of the other.

This objection is similar to the following conundrum:

Is the sin of any man committed with the will of God or against it? If he answers "with the will of God," then every sinner ought to find favour with God; if he says "against the will of God," then God is not supreme. In other words the dilemma proposed by the Rabbi is precisely the same as that of the existence of evil, and the commission of any act of sin.

Of course, this ignores the distinction between what God desires and what he permits. If "with the will of God" means "with the permission of God" then in that sense we sin with the will of God. We have been given free will, meaning that our will is not deterministic. God permits us to act against him because he respects our freedom.

Getting back to the issue at hand, why would Jesus have prayed as he did if he undertook this mission of redemption? It shows that Jesus had human emotions and feelings. He did not try to escape what was coming to him. Even in the exact same chapter (Matthew 26), we see the following:

Jesus said to him, “Friend, do what you came to do.” Then they came up and laid hands on Jesus and seized him. And behold, one of those who were with Jesus stretched out his hand and drew his sword and struck the servant of the high priest and cut off his ear. Then Jesus said to him, “Put your sword back into its place. For all who take the sword will perish by the sword. Do you think that I cannot appeal to my Father, and he will at once send me more than twelve legions of angels? But how then should the Scriptures be fulfilled, that it must be so?” (Matthew 26:50-54)

Jesus was still in control, but that did not change the fact that he still felt fear, just as he felt temptation when confronted by Satan earlier. Fear causes us to act irrationally, and the mark of bravery is not that we do not feel fear, but that we act wisely in spite of that fear.
 
A. Lukyn Williams also adds the following remark:

Why was Jesus troubled if it was His will to suffer? What? Did the Rabbi never make up his mind to perform a difficult task, and yet shrink from it, even pray God that he might not have to carry out his purpose? I have no doubt that as a God-fearing Jew he did. And should not Jesus (man in the truest and fullest sense, though also God) shrink from what was ten thousand times worse for Him than for men generally, death, with the hiding of that Face for a moment, in the light of which He had up to that time continuously walked?