Numbers 5:18-19

The priest shall then have the woman stand before the LORD, and let the hair of the woman’s head hang loose, and put the memorial grain offering in her hands, which is the jealousy offering, and in the hand of the priest is to be the water of bitterness that brings a curse. Then the priest shall have her take an oath and say to the woman, “If no man has lain with you and if you have not gone astray into uncleanness [while married], then be immune to this water of bitterness that brings a curse