Numbers 5:18

and the priest shall set the woman before the Lord, and uncover the woman's head, loosen her hair as a symbol of the suspicion of unfaithfulness and of the suspension of the husband's protection for the time being, and put the offering of memorial in her hands, which is the jealousy offering, the barley signifying the suspicious character of the behavior of which she is accused, and she herself, as it were, holding in her hands the fruit of her actions and placing it before the Lord for judgment. And the priest shall have in his hand the bitter water that causeth the curse, to signify that, if she be guilty, the bitter suffering of God's curse would strike her;