Asking eight of the disciples to sit down, Jesus took Peter, James and John, and they went farther into the garden. These three, who seem to form the inner circle, had been with Him on the mount of transfiguration (Matthew 17:1-9), had seen the girl raised at the house of Jairus (Matthew 9:18-25), and were apparently the three from whom Jesus could most expect sympathy and understanding in this hour. — Walvoord, page 216.
deeply distressed (v.37) — Most probably it has come from one word that means “away from home.” He began to be sorrowful and away from home. It means more than that, of course; but that is the root idea, that of desolating loneliness. He began to enter into that consciousness of His absolute isolation. — Morgan, page 302.
watch (v.41) = keep watching
Christ’s prayer in the garden to have the cup pass from Him while at the same time submitting totally to the Father’s will has to be one of the most difficult to comprehend passages of Scripture. It certainly displays His total humanity while demonstrating His complete unity with the Father in deity. I don’t think it’s possible for us get to the bottom of what it means, but here are two attempts.
That a sinless Being should have any contact with sin (John 8:46); and further, should be loaded with sin (1 Peter 2:24); and, most dreadful of all, should be constituted sin (John 3:14 and 2 Corinthians 5:21), must have been unspeakable agony. Hebrews 5:7, and several of the Psalms, support the belief that the horror of being forsaken by God (Psalm 22:1) and cast into hell was so great that He could not, as a man, have endured it but for added angelic strength (Luke 22:43-44); yet was there no antagonism between His independent will and the will of the Father. — Williams, page 726.
Adam’s penalty for sin was death. This included both physical and spiritual death. Men are born into the world spiritually dead and therefore are subject to physical death. If Christ was to provide salvation for sinners, He had to partake of death on their behalf (Hebrews 2:9). When He went to the cross, He vicariously bore both aspects of death for sinners. He endured spiritual death on the cross, that is, the separation of His soul from the Father. The evidence that He bore spiritual death is seen in His cry, “My God, My God, Why have you forsaken me? (Matthew 27:45). Christ also experienced physical death (Matthew 27:50; John 19:33). Thus we see that Christ died both spiritually and physically because He died as the sinners’ substitute. The penalty that God had intended for sinners fell on God’s own Son. The penalty for sin is eternal separation from God. This eternal separation is called “the second death” (Revelation 20:14). God would have been just if He had demanded that Christ, who tasted death for every man, be eternally separated from Himself. Christ prayed that God might accept His death as a full payment of the sin of sinners and bring Him out of death and restore Him to life again. Thus the prayer should be understood the be a prayer for restoration to physical life by resurrection, and a restoration to full fellowship with His Father out of the spiritual death into which He would enter. The evidence that God answered Christ’s prayer is seen, first, in the fact that Christ was raised from the dead on the third day and given a glorified body. Second, it is seen in the fact that on the fortieth day He ascended to the Father to be seated at His right hand in glory.
If it be objected that restoration to life and to fellowship or deliverance from physical and spiritual death meant that God exacted less of Christ in payment for sin than God would exact from the sinner, let it be noted that the life that Christ offered to the father was His own eternal kind of life. Therefore Christ made an eternal offering for sins even though that offering was accomplished in a few moments of time. This explanation seems to meet the demands of Hebrews 5:7, which states that His prayer was answered.
It did involve physical death, being made sin, being separated from the Father, and entering into the fullness of death, both physical and spiritual, for us. While we cannot comprehend all that was entailed, we can take note of the unquestioned and implicit obedience of the Son, who said three times to His Father, “Not what I will, but what you will” (Mark 14:36). Because of this, Paul could say He “became obedient to death — even death on a cross! — Pentecost, pages 455-456.
What we can be sure of is that Christ was not asking to be excused from the cross. That would be counter to His entire ministry. But that He was dreading His exposure to sin and His separation from the Father takes nothing away from His willingness to endure it.