Numbers 5:18-19

And the priest shall set the woman before the LORD and unbind the hair of the woman’s head and place in her hands the grain offering of remembrance, which is the grain offering of jealousy. And in his hand the priest shall have the water of bitterness that brings the curse. Then the priest shall make her take an oath, saying, ‘If no man has lain with you, and if you have not turned aside to uncleanness while you were under your husband’s authority, be free from this water of bitterness that brings the curse.