The Hands were Washed in Token of Innocency
Source: TTT
Deuteronomy 21:6, 7
Then all the elders of the city nearest the victim shall wash their hands by the stream over the heifer whose neck has been broken, / and they shall declare, “Our hands did not shed this blood, nor did our eyes see it.
Matthew 27:24
When Pilate saw that he was accomplishing nothing, but that instead a riot was breaking out, he took water and washed his hands before the crowd. “I am innocent of this man’s blood,” he said. “You bear the responsibility.”