When Jesus was having his Last Supper with his apostles, he said that one of them would betray him.
There were a lot of people that did not like Jesus, and some of them wanted to have him killed, but they wanted someone like one of his apostles to tell them where he was.
Jesus knew that Judas would be the one who would do it, so at the last supper he told his apostles that Judas was the one who would betray him.
Judas left the supper and went to tell the people who wanted to kill Jesus where he was.
(from: wikipedia - last supper)
Kid Facts - Blast from the past: Jesus' Apostles - Judas Iscariot
