Numbers 5:18-19

The priest will make the woman stand before the LORD, and he will loosen her hair. He will hand her the offering of remembrance, the grain offering for jealousy; he will hold the bitter water that brings a curse. The priest will make her take an oath and ask her, “Has another man had sexual relations with you? Have you been unfaithful to your husband? If you haven’t, this bitter water that brings a curse won’t hurt you.