What does Matthew 26:49 mean?

Judas Iscariot earns the name he will carry for all of history. Jesus and Matthew have called him "the betrayer" (Matthew 26:46, 48) and now he carries out the role. This was a moment arranged by Judas (Matthew 26:14–16) for reasons that are not entirely clear. He was paid for his betrayal, but not an outrageous amount. He may have been disillusioned with Christ's refusal to trigger rebellion against Rome. He may have become bitter and doubtful. It might have been a combination of all three: greed, disappointment, and spite. All we know for sure is that Satan tempted Judas, one of Christ's closest companions, to hand Him over to death (John 13:2, 26–27).

The sign used to identify Jesus was arranged beforehand (Matthew 26:48). Jesus was known by name and by reputation, but this was long before photographs or extremely diverse clothes. Judas needed to do more than just tell others where Jesus was; he needed to directly aim the mob at the right person.

This moment multiplies the awful, hateful nature of Judas' choice. This is meant to be an expression of mutual trust and friendship, and the words he uses are meant to show respect. Other gospel writers offer additional details. Luke reports (Luke 22:48) that Jesus asks pointedly, "Judas, would you betray the Son of Man with a kiss?" Jesus didn't want Judas to miss the weight of what he was doing. Not only is he acting as a traitor, but he's also doing it using a vile perversion of pretended love.