And the LORD spoke to Moses, saying, “Speak to the people of Israel, If any man’s wife goes astray and breaks faith with him, if a man lies with her sexually, and it is hidden from the eyes of her husband, and she is undetected though she has defiled herself, and there is no witness against her, since she was not taken in the act, and if the spirit of jealousy comes over him and he is jealous of his wife who has defiled herself, or if the spirit of jealousy comes over him and he is jealous of his wife, though she has not defiled herself, then the man shall bring his wife to the priest and bring the offering required of her…
“And the priest shall bring her near and set her before the LORD. And the priest shall take holy water in an earthenware vessel and take some of the dust that is on the floor of the tabernacle and put it into the water. 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. But if you have gone astray, though you are under your husband’s authority, and if you have defiled yourself, and some man other than your husband has lain with you, then’ (let the priest make the woman take the oath of the curse, and say to the woman) ‘the LORD make you a curse and an oath among your people, when the LORD makes your thigh fall away and your body swell. May this water that brings the curse pass into your bowels and make your womb swell and your thigh fall away.’ And the woman shall say, ‘Amen, Amen.’
“Then the priest shall write these curses in a book and wash them off into the water of bitterness. And he shall make the woman drink the water of bitterness that brings the curse, and the water that brings the curse shall enter into her and cause bitter pain. And the priest shall take the grain offering of jealousy out of the woman’s hand and shall wave the grain offering before the LORD and bring it to the altar. And the priest shall take a handful of the grain offering, as its memorial portion, and burn it on the altar, and afterward shall make the woman drink the water. And when he has made her drink the water, then, if she has defiled herself and has broken faith with her husband, the water that brings the curse shall enter into her and cause bitter pain, and her womb shall swell, and her thigh shall fall away, and the woman shall become a curse among her people. But if the woman has not defiled herself and is clean, then she shall be free and shall conceive children.
“This is the law in cases of jealousy, when a wife, though under her husband’s authority, goes astray and defiles herself, or when the spirit of jealousy comes over a man and he is jealous of his wife. Then he shall set the woman before the LORD, and the priest shall carry out for her all this law. The man shall be free from iniquity, but the woman shall bear her iniquity.” (Numbers 5:11-31 ESV)
There are times when the purity in the camp cannot be determined except by a trial by ordeal. In the case of a jealous husband who is suspicious that his wife has been unfaithful, Yahweh gives a test. If the wife drinks the concoction described here and does not get sick, she is innocent. Her husband’s jealousy is exposed as unfounded. He is the uncleanness in the camp, not her. If she is guilty her womb will swell, her thigh fall away and she will be childless, a consequence of her infidelity.
It may be argued that this was a very male-centric regulation. What if the woman was suspicious of her husband? Could she have him drink the potion? But in another sense this was a protection for the woman. Mere jealousy on the part of her husband would not justify mistreatment. This provided a definitive test and protected her from wrongful accusations.
God is concerned for the just treatment of those who are in the position of little or no power. He does not hold guiltless the one who abuses his power. We must not abuse the power we have but always use it for the benefit of others, not ourselves.