What does Mark 14:44 mean?

It is late night or very early morning on the Mount of Olives, and the time has come for Judas to betray Jesus to the Jewish rulers. It's dark. The Mount of Olives is inhabited by some of the tens of thousands who have come to celebrate the Passover in Jerusalem. Jesus is surrounded by eleven of His disciples. Judas needs a way to identify Jesus so the servants and guards of the Jewish leadership can get close enough to Jesus to arrest Him without the disciples helping Him escape. In an era without photographs, it's also necessary to bring someone along who can directly identify Jesus to the authorities.

Judas needs to get the guards close because he knows Jesus can be hard to catch. In Nazareth, the people reacted so negatively to Jesus' teaching that they tried to throw Him off a cliff. Jesus simply walked through the crowd and left (Luke 4:16–30). The religious leaders in Jerusalem know Jesus can be elusive, when it comes to being physically captured. At least twice He slipped out of their grasp when they had resolved to stone Him (John 8:59; 10:31, 39). Neither the Jewish leaders nor Judas understand that the reason they couldn't catch Jesus before wasn't because they were unprepared but because it wasn't time for them to catch Him yet (John 7:30).

To identify Jesus in the dark, surrounded by the disciples, Judas uses the traditional greeting of respect, honor, and brotherly love. The groggy disciples would recognize Judas and think he is returning from buying the supplies for the Feast of Unleavened Bread to be celebrated the next evening (John 13:27–30). The kiss would further lower the disciples' guard long enough for the crew of arresting guards to reach Jesus. The disciples are completely unprepared for what is about to happen.