What is the Gospel of Judas?
The text is a fourth-century manuscript of a Gospel that we know was in existence by the year 180, because [church leader] Irenaeus wrote about it in Against Heresies. It's an effort to rehabilitate Judas by a group known as Cainite Gnostics. They habitually tried to rehabilitate figures described negatively in the Bible, including Cain and the Sodomites. This work doesn't tell us anything about the historical Jesus or the historical Judas.
Because it's dated later, it doesn't go back to Judas, and we can't really trace the tradition line to be confident of it.
What does the text say?
The text basically has Jesus tell Judas to [betray him] because it will help accomplish the will of God. I think this is an expansion on the Gospels where Jesus says to "go and do this quickly" at the Last Supper, because Judas has already made his commitment.
How has the church viewed Judas through history?
Judas has sometimes been used in history as a basis for anti-Semitism, and that should not be excused. However, we need to distinguish between what separated Judaism and Christianity, and what emerged later out of that story. During the first-century messianic Jewish movement, I think Judas came to the point where Jesus was not the kind of Messiah that he expected. He was disappointed, so he went to the Jewish officials, because he feared Jesus would take Judaism with him. I view Judas not so much as a villain but as a tragic figure who made a very bad decision about Jesus. It's not something so much to shake your finger at, but something to be sad about.
More on the Gospel of Judas includes:
Books & Culture's Books of the Week
Betrayed Again | The Gospel of Judas Roadshow.
The Jesus and Judas ...