Here are three synoptics' takes on Jesus' prayer in Gethsemane:
Matthew 26:38-39, "“I am deeply grieved, even to death;” ...“My Father, if it is possible, let this cup pass from me; yet not what I want but what you want.”
Mark 14:34-36, "I am deeply grieved, even to death;" … “Abba, Father, for you all things are possible; remove this cup from me; yet, not what I want, but what you want.”
Luke 22:42, “Father, if you are willing, remove this cup from me; yet, not my will but yours be done.”
While there is no such equivalent scene related in the fourth gospel, there is the following line in Jesus' discourses about his death:
John 12:27, “Now my soul is troubled. And what should I say—‘Father, save me from this hour’? No, it is for this reason that I have come to this hour.
This seems like a direct commentary on the apparent difference between Jesus' will and God's will in the synoptics. It also doesn't seem to be said for the benefit of anyone but the reader and seems to reference special knowledge (e.g. of the Gethsemane tradition). There is a broader theme in John of Jesus being completely obedient to god to the point that his will and God's will are identical (there is no conflict, Jesus is an empty conduit to the Father). For example:
John 5:30, “I can do nothing on my own. As I hear, I judge; and my judgment is just, because I seek to do not my own will but the will of him who sent me.
John 10:30, "The Father and I are one."
It seems to me that John had awareness of either the synoptics, or the tradition from which the synoptics drew their common Gethsemane narrative (e.g. the one behind Mark). What do you think? How do you interpret this difference?