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.
Jesus
The Gospels say that Jesus was betrayed to the authorities by a disciple, and many scholars consider this report to be highly reliable. He was executed on the orders of Pontius Pilate, the Roman prefect of Judaea. Pilate most likely saw Jesus' reference to the Kingdom of God as a threat to Roman authority and worked with the Temple elites to have Jesus executed. The Sadducean high-priestly leaders of the Temple more plausibly had Jesus executed for political reasons than for his teaching. They may have regarded him as a threat to stability, especially after he caused a disturbance at the Second Temple. Other factors, such as Jesus' triumphal entry into Jerusalem, may have contributed to this decision. Most scholars consider Jesus' crucifixion to be factual, because early Christians would not have invented the painful death of their leader.