Why Did Judas Need to Identify Christ?

First of all, Jerusalem had hundreds of thousands of people, maybe millions during the celebrations and festivals. Even if Jesus were known by sight to tens of thousands, He still would not have been easily recognized by sight to the guards (cohort) that came to arrest him. Unlike today, no photos, no T.V. No widespread recognition except on coins, perhaps.

Most of those who knew of Him and His miracles may have never been able to get close enough, long enough to recognize him.

Second: Think like the soldiers. They came at night, which would make recognition even more difficult. They may have feared that storming the area might cause confusion and He might escape in the darkness. If they arrested everyone, but He escaped, He would be tipped off that He had been betrayed. Remember, they had tried to sieze Him before, but were unable.

Thirdly: Theologically, the betrayal was powerfully portrayed in a very intimate way. He betrayed Him with a kiss. A sign of great affection and devotion. By our mouths we praise Him but our hearts are black, so to speak. Only God knows the hearts of men.