Exodus 19:10

εἶπεν δὲ κύριος πρὸς Μωυσῆν καταβὰς διαμάρτυραι τῷ λαῷ καὶ ἅγνισον αὐτοὺς σήμερον καὶ αὔριον καὶ πλυνάτωσαν τὰ ἱμάτια