Judas Iscariot
There are several explanations as to why Judas betrayed Jesus. In the earliest account, in the Gospel of Mark, when he goes to the chief priests to betray Jesus, he is offered money as a reward, but it is not clear that money is his motivation. In the Gospel of Matthew account, on the other hand, he asks what they will pay him for handing Jesus over. In the Gospel of Luke and the Gospel of John, the devil enters into Judas, causing him to offer to betray Jesus. The Gospel of John account has Judas complaining that money has been spent on expensive perfumes to anoint Jesus which could have been spent on the poor, but adds that he was the keeper of the apostles' purse and used to steal from it.
Islamic views on Jesus' death
According to the Gospel of Barnabas it was Judas, not Jesus, who was crucified on the cross. This work states that Judas' appearance was transformed to that of Jesus', when the former, out of betrayal, led the Roman soldiers to arrest Jesus who by then had already ascended to the heavens. The narrative states this transformation of appearance was unnoticed by the followers of Christ and his mother Mary. The Gospel of Barnabas then mentions that after three days since burial, Judas' body was stolen from his grave with rumors spreading of Jesus being risen from the dead. In following with Islamic lore, when Jesus was informed in the third heaven about what happened he prayed to God to be sent back to the earth, and later descended and gathered his mother, disciples, and followers and told them the truth of what happened. He then ascended back to the heavens, with the narrative continuing Islamic legend mirroring Christian doctrine of returning at the end of times as a just king.