What does Mark 14:57 mean?

The trial against Jesus before the Sanhedrin is a sham on many different levels.

First is the motivation for the trial. Since early in His ministry, the Pharisees have wanted Jesus destroyed because He rejects their manmade traditions. Herodians fear He will lead an uprising against Herod Antipas, their tetrarch (Mark 3:6). The Sadducees are afraid He will threaten their good relationship with Rome. The elders—mostly merchants and businessmen—resent that He tore down the stalls in the Court of the Gentiles (Mark 11:15–19). The trial has nothing to do with Jesus breaking the Law and everything to do with how He threatens their worldly position.

Second, the trial itself is illegal. The purpose of a trial is to determine "if" the defendant is involved in a known crime, using witnesses and evidence. This trial is backwards: it presumes Jesus has committed some crime, and seeks to justify that prejudice.

Third, while the Sanhedrin tries to find two witnesses who agree on how Jesus has committed a capital offense, those witnesses are committing a capital offense. In the section of the Mosaic law on false witnesses, it says, "if the witness is a false witness and has accused his brother falsely, then you shall do to him as he had meant to do to his brother" (Deuteronomy 19:18–19). The witnesses are purposefully trying to convict Jesus of a capital offense; since their witness is false, they should be executed, according to the letter of the law.

Finally, so long as Roman authority rules over Jewish territory, the Jews are not permitted to execute anyone, anyway. The involvement of the Sanhedrin might justify their acts to the Jewish people, but it removes the possibility of having Jesus killed in secret—with His popularity, such news would eventually reach Roman ears and result in consequences. Due to the public nature of these events, the Romans would have to carry out an actual death sentence. But that, in turn, makes any blasphemy the Sanhedrin ties to Jesus useless—the Romans don't care about the Jewish God (John 18:33–35). The Sanhedrin will have to invent an entirely different civil accusation in order to convince the governor, Pilate, to put Jesus to death.

Ironically, the chief priest, Caiaphas, gave the true reason for the trial earlier when the Jewish leaders had gathered to conspire against Jesus: "You know nothing at all. Nor do you understand that it is better for you that one man should die for the people, not that the whole nation should perish" (John 11:49–50). God inspired him to say these words, but not for the reason Caiaphas assumed. God sent Jesus to die not so that the Romans wouldn't destroy Jerusalem. He sent Jesus so that the sins of the world could be forgiven (John 11:51–52).