What does Mark 15:2 mean?

In Roman courts in outlying areas, non-appointed native magistrates can opt to enforce their own ceremonial laws and some civil laws, in addition to Roman requirements. However, while they can accuse someone of a capital offense, they cannot execute anyone. Only an appointed Roman official can authorize capital punishment. The Sanhedrin, the Jewish ruling council, has convicted Jesus of the crime of claiming to be "the Christ, the Son of the Blessed" (Mark 14:61). "Christ" is Greek for Messiah, but that word has no context, yet. At this point in human history, the term would mean nothing to Pilate, or virtually anyone other than the Jewish people.

Pilate's limited understanding of Judaism seems primarily tied to ways to offend them. He probably has an unclear understanding of the Jewish Messiah. This might also be why he sends Jesus to Herod Antipas (Luke 23:6–12). When a local authority brings charges to a Roman magistrate, they usually go through an interpreter. The interpretation the translators use, then, is "King of the Jews." When Pilate places the sign "King of the Jews" above Jesus' head on the cross, he is making a legal declaration: that Jesus dies because He claims to be the Messiah.

The claim that Jesus is king of the Jews began with the wise men (Matthew 2:2). Jesus has affirmed that claim (Matthew 20:21; Mark 9:1) and the travelers to Jerusalem believe it (Mark 11:10). In addition, every time Jesus calls Himself the "son of man," He is claiming to be the figure spoken of in Daniel 7:13–14. The Ancient of Days will give the son of man "dominion and glory and a kingdom, that all peoples, nations, and languages should serve him…" (Daniel 7:14). That would put Caesar and Rome under Jesus' authority.

As he often does, John gives more detail (John 18:34–38). When Pilate asks Jesus if He is king of the Jews, Jesus makes the question personal and asks if Pilate is inquiring on his own behalf. This is a not-so-subtle reminder that Pilate is acting on the accusations of others, not his own knowledge. Jesus is also giving Pilate the opportunity to see the truth of who He is. Jesus explains that His kingdom is not earthly, but it is real. Pilate realizes Jesus is not a threat to him or Caesar. He tries to get Jesus to defend Himself against the accusations of the Sanhedrin. But, to the end, Jesus is more concerned about the heart right in front of Him.

Jesus' refusal to defend Himself has another result: it protects His own enemies. Pilate can rightly be accused of many things, including ineptness and cowardice—but he's not stupid. He knows the Sanhedrin's charges are false. If Jesus affirms this, His accusers can be convicted of calumnia or false witness. The punishment for such a charge is to face the same punishment the defendant would have received. Pilate could, had he been willing to pursue the matter, have crucified the chief priests, scribes, and elders!