Numbers 5:18-19

5:18 Then the priest will have the woman stand before the Lord, uncover the woman’s head, and put the grain offering for remembering in her hands, which is the grain offering of suspicion. The priest will hold in his hand the bitter water that brings a curse. ¹  5:19 Then the priest will put the woman under oath and say to the her, “If no other ²  man has had sexual relations with you, and if you have not gone astray and become defiled while under your husband’s authority, may you be free from this bitter water that brings a curse. ³ 

Numbers 5:27

5:27 When he has made her drink the water, then, if she has defiled herself and behaved unfaithfully toward her husband, the water that brings a curse will enter her to produce bitterness – her abdomen will swell, her thigh will fall away, and the woman will become a curse among her people.

[5:18]  ¹ tn The expression has been challenged. The first part, “bitter water,” has been thought to mean “water of contention” (so NEB), but this is not convincing. It has some support in the versions which read “contention” and “testing,” no doubt trying to fit the passage better. N. H. Snaith (Leviticus and Numbers [NCB], 129) suggests from an Arabic word that it was designed to cause an abortion – but that would raise an entirely different question, one of who the father of a child was. And that has not been introduced here. The water was “bitter” in view of the consequences it held for her if she was proven to be guilty. That is then enforced by the wordplay with the last word, the Piel participle הַמְאָרֲרִים (ham’ararim). The bitter water, if it convicted her, would pronounce a curse on her. So she was literally holding her life in her hands.

[5:19]  ² tn The word “other” is implied, since the woman would not be guilty of having sexual relations with her own husband.

[5:19]  ³ sn Although there would be stress involved, a woman who was innocent would have nothing to hide, and would be confident. The wording of the priest’s oath is actually designed to enable the potion to keep her from harm and not produce the physical effects it was designed to do.