What does Mark 15:1 mean?

The Jewish leadership has been trying to destroy Jesus since early in His ministry (Mark 3:22–30). At least twice, they have been prepared to stone Him (John 8:59; 10:31). They don't want to execute Jesus during the Passover and week-long Feast of Unleavened Bread (Mark 14:1–2); Jesus has too many supporters who may cause a riot (Mark 11:1–10; 14:1–2). But since they have Him, it is much better if He is executed quickly.

The Sanhedrin has a lot working against them. If they imprison Jesus, His followers could rile up the travelers from Galilee, Judea, and the surrounding area who at least think He is a prophet, if not the Messiah. Because of Jesus' popularity, the number of Galileans in Jerusalem, and the fact that the Jewish council cannot execute someone, they need the Romans to kill Jesus. Were Jesus less-renowned and less-connected to conflict with religious leaders, they likely would have been content to let a mob break Roman law by stoning (Acts 7:54–60). Roman officials hold their trials in the early morning; if the Sanhedrin waits until later in the day, Pilate will not be available. At evening the Sabbath begins, so they need to move fast.

This verse does not describe a second trial before the Sanhedrin. The trial in Mark 14:53–65 happens concurrently with Peter's denials in Mark 14:66–72. "Held a consultation" means the evidence-gathering is over and the council members are making their final decision. They have already convicted Jesus of blasphemy according to the Mosaic law (Mark 14:63–65). Likely this discussion is to decide on what capital offence against Roman law they will present before Pilate.

John, who may have been present, adds more detail (John 18:28–32). When the members of the Sanhedrin take Jesus to Pilate's house, they do not enter. As residents of Jerusalem, they eat the Passover that afternoon, and will become unclean if they enter the home of a Gentile. After Pilate interviews and flogs Jesus, the Sanhedrin makes their case again (John 19:6–7). They want Pilate to execute Jesus. Pilate, either sarcastically or tauntingly, tells them to do it. They had earlier stated that by Roman law, they do not have the authority to execute someone. Now they tell Pilate that Jesus has committed an offense that, by Jewish law, is deserving of death—He has claimed to be the Son of God. By handing Jesus over to be crucified, His direct prophecy of crucifixion is fulfilled (John 18:32; Matthew 20:19) as well as the vaguer references to the crucifixion of the Messiah in the Mosaic law (Deuteronomy 21:22–23; Galatians 3:13).