this is also a prefigurement of the mikveh, which saves you (PL) now, not the removal of impurity from the body, but the desire/request for a good conscience in relation to Hashem, through the standing up again (from the dead) of Yehoshua the Moshiach;
and when Pilate has seen, that he was achieving nothing, only that it becomes a greater turmoil, has he taken water and self washed the hands before the crowd people, and said: I am innocent concerning the this tsaddik's blood; you (PL) see.