Who arrested Jesus?  
Matthew 26:47; Mark 14:43; Luke 22:47; John 18:12

1. A multitude
   1. (Matt. 26:47,50) - "And while He was still speaking, behold, Judas, one of the twelve, came up, accompanied by a great multitude with swords and clubs, from the chief priests and elders of the people . . And Jesus said to him, "Friend, do what you have come for." Then they came and laid hands on Jesus and seized Him."
   2. (Mark 14:43) - "And immediately while He was still speaking, Judas, one of the twelve, came up, accompanied by a multitude with swords and clubs, from the chief priests and the scribes and the elders."
   3. (Luke 22:47) - "While He was still speaking, behold, a multitude came, and the one called Judas, one of the twelve, was preceding them; and he approached Jesus to kiss Him."
2. Roman cohort, commander, and Jewish officers.
   1. (John 18:12) - "So the Roman cohort and the commander, and the officers of the Jews, arrested Jesus and bound Him,"

     This is obviously no biblical contradiction.  Matthew, Mark, and Luke tell us that a multitude approached Jesus in the garden and they seized Him.  John tells us that the arresting party was "the Roman cohort and the commander, and the officers of the Jews..."  Obviously, the multitude included those who were actually doing the arresting.