If Jesus died at 3pm what is the significance of 3AM?

John Shelby Spong (Jesus for the NonReligious) describes a structure in which Mark divides the last twenty-four hours before the death of Jesus into eight segments of three hours each:

A The celebration of the Passover Feast, which becomes the Last Supper, beginning "when it was evening" (Mark 14:17), or when the sun went down: approximately 6 pm and the beginning of the day of the Passover by Jewish reckoning. Mark knew that the duration of the Passover meal was three hours and that it concluded with the singing of a hymn. Jesus says, "This is my body," a metaphor that will be reflected in his burial (A').

..B When was about 9 p.m. Mark then has Jesus and the disciples go to the Garden of Gethsemane, where Jesus went to pray. He suffered alone and in agony, asking God that, if possible, he take this cup (his destiny to be crucified) away from Jesus. Meanwhile his disciples, Peter, James and John, were not able to remain awake. "Could you not watch one hour?" Jesus asked. The process was repeated two more times. The disciples could not watch one, two or three hours. It was now midnight.

....C The betrayal of Jesus, the darkest deed in human history, came next, occurring at the stroke of midnight. This will be reflected by the darkness at midday.

......D At 3:00 a.m., Jesus was led away for a trial before the high priest and other senior priests and elders. We know the time of the first trial because Peter's threefold denial of Jesus followed, once each hour until the cock crowed, marking the watch between 3 a.m. and 6 a.m., known as cockcrow.

........E "As soon as it was morning", which meant 6 o'clock, Jesus was led by the chief priests, scribes and elders for trial by Pontius Pilate.

......D' At 9 o'clock: "It was the third hour when they crucified him."

....C' When "the sixth hour had come" (12 noon), darkness covered the whole earth, reflecting the betrayal at 12 midnight.

..B' The three hours of darkness, until 3 p.m. mirror the agony in the Garden of Gethsemene. Jesus last words, "My God. My God, why hast thou forsaken me?" reflect the recognition that his prayer in the Garden has not been answered. At 3 o'clock Jesus cried out and gave up the ghost.

A' Joseph of Arimathea then asked Pilate for the body of Jesus, so that he could be buried before the Sabbath began at 6 p.m., when the sun went down.

Notice that in this chiastic structure, the arrest of Jesus at 3 AM forms a pair (pair D) with the act of crucifying Jesus. The death of Jesus at 3 PM is the second event of pair B, matching Jesus going to pray in the Garden of Gethsemane; asking God that, if possible, he take this cup (his destiny to be crucified) away from him, and matching his last words "My God. My God, why hast thou forsaken me?".

if 3pm is the time of Jesus' death, Jesus being the son, or messanger for god, it would make sense that 3am would be the time for demons, 3am is the exact opposite to 3pm. and demons are the messangers for Satan, the exact opposite to Jesus. its all about opposites:) that's what I think:)

You are correct in almost all of that. The thing to add is that at 3am is also when Satan appeared to Chirst in the Garden the morning of good Friday. It was then 12 hours later that he commended his spirit to the Father. 3am has become known by exorcist as the bewitching hour. When demonic activity is at its highest