Matthew 27:6 These chief priests felt no guilt in giving Judas money to betray an innocent man, but when Judas returned the money, the priests couldn't accept it because it was wrong to accept blood money-payment for a murder. Their hatred for Jesus had caused them to loose all sense of justice.
Matthew 27:9, 10 This prophecy is found specifically in Zechariah 11:12, 13, but it also may have been taken from Jeremiah 17:2, 3; 18:1-4, 19:1-11; or 32:6-15). In Old Testament times, Jeremiah was considered the collector of some of the prophets writings, so perhaps his name is cited rather than Zechariah.
Matthew 27:12 Standing before Pilate, the religious leaders accused Jesus of a different crime than the ones for which they had arrested Him. They arrested Him for blasphemy, but that charge would mean nothing to the Romans. So the religious leaders had to accuse Jesus of crimes that would have concerned the Roman government, such as encouraging the people not to pay taxes, claiming to be a king, and causing riots. These accusations were not true, but the religious leaders were determined to kill Jesus, and they broke several commandments in order to do so.
Matthew 27:14 Jesus' silence fulfilled the words of the prophet (Isaiah 53:7). Pilate was annoyed that Jesus didn't try to defend Himself. He recognized the obvious plot against Jesus and wanted to let Him go, but Pilate was already under pressure from Rome to keep peace in his territory. The last thing he needed was a rebellion over this quiet and seemingly insignificant man.