Numbers 5:18-19

After the priest has had the woman stand before the LORD, he shall loosen her hair and place in her hands the reminder-offering, the grain offering for jealousy, while he himself holds the bitter water that brings a curse. Then the priest shall put the woman under oath and say to her, “If no other man has had sexual relations with you and you have not gone astray and become impure while married to your husband, may this bitter water that brings a curse not harm you.