The Prayer and The Cup
Matthew 26:39 (ESV) … “And going a little farther he fell on his face and prayed, saying, “My Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as you will.”
“Prayer is a shield to the soul, a sacrifice to God, and a scourge to Satan” … John Bunyan
Jesus went still farther into the garden to be alone with God. His agony was such that he threw himself on the ground before God in deep spiritual anguish, praying that if possible let this cup pass—in other words, he was asking the Father to let the mission be accomplished some other way not requiring the agony of crucifixion, when he would become sin and be separated from the Father. In the Old Testament, “cup” stood for the trial of suffering and the wrath of God (Isaiah 51:17). So Jesus referred to the suffering that he must endure as the “cup” he would be required to drink. Yet Jesus humbly submitted to the Father’s will. He went ahead with the mission for which he had come (1:21).
With the words “let this cup pass from Me,” Jesus was referring to the suffering, isolation from God, and death he would have to endure in order to atone for the sins of the world. Jesus, as God’s Son, recoiled from sin, yet part of his task would be to take the sins of the whole world upon himself. This was a cup he truly hated to drink. In addition, Jesus, as God’s Son, knew constant fellowship with the Father. Yet for a time on the cross he would have to be deprived of that fellowship. This was a bitter cup. The physical suffering would be horrible enough (Hebrews 5:7–9), but God’s Son also had to accept the cup of spiritual suffering—bearing our sin and being separated from God (27:46).
Yet Jesus was not trying to get out of his mission. Jesus was expressing his true feelings as a human being, but he was not denying or rebelling against God’s will. (Jesus may have been referring to Isaiah 51:22, where God lifted the cup of judgment for the righteous in Jerusalem.) He reaffirmed his desire to do what God wanted by saying, Nevertheless, not as I will, but as You will. Jesus’ prayer reveals his terrible suffering. Jesus paid for sin by being separated from God. The sinless Son of God took our sins upon himself to save us from suffering and separation. [1]

[1] Barton, B. B. (1996). Matthew (pp. 522–523). Wheaton, IL: Tyndale House Publishers.