Matthew 27:24

Washing one’s hands to symbolize one’s innocence was a Jewish custom, not a Roman custom (cf. Deuteronomy 21:6; Psalms 26:6). [Note: Carson, "Matthew," p. 570.] Evidently Pilate did this to show contempt for the Jews. Pilate could wash his hands with a clear conscience because he had tried to release Jesus, but the Jews would not allow him to do so. This is not saying he was innocent of guilt, but he undoubtedly felt justified in doing what he did. Pilate delivered Jesus up for crucifixion out of cowardice and fear of the Jews whom he despised. He could no more pass his personal responsibility for Jesus’ death off on the people than the chief priests and elders could avoid their responsibility for it by blaming Judas (Matthew 27:4).