Putting an object into someone's hand is a metaphor for allowing that person to do what he wants with that object. Here the reader should understand that Cyrus expected Mithredath to do what Cyrus wanted him to do. Alternate translation: "put Mithredath the treasurer in charge of them" or "made Mithredath the treasurer responsible for them" (See: [[rc://en/ta/man/translate/figs-metaphor]])