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.
Matthew 27:6
Unlike Judas at , the priests do not acknowledge that was "innocent blood" that the money paid for, but their actions do convey that they are aware the betrayal of Jesus was a treacherous act. This verse builds upon the theme that Jesus is innocent, and that in the Gospel of Matthew the Jewish leaders are condemning him despite also knowing his innocence. In John Calvin's commentary on Matthew he reads gross hypocrisy in the priests worrying about the impurity of the coins while conspiring to execute Jesus.