Numbers 5:21
Then the priest shall charge the woman with an oath of cursing, and the priest shall say unto the woman, The LORD make thee a curse and an oath among thy people, when the LORD doth make thy thigh to rot, and thy belly to swell; Then the priest shall charge the woman with an oath of cursing, and the priest shall say unto the woman, The LORD make thee a curse and an oath among thy people, when the LORD doth make thy thigh to rot, and thy belly to swell;
Numbers 5:21 belongs to the law for a woman accused of adultery, the test of jealousy appointed for a suspected wife. In that test the priest puts the accused woman under a judicial oath of cursing, by which she is made subject to a curse if she is guilty. The priest has authority to administer this oath in a case of alleged criminality, which shows that judicial oaths were instituted under Moses. The stated sign of the curse is bodily, that her belly shall swell and her thigh shall rot or waste away.
If the woman was guilty, the bitter water would bring that bodily curse upon her unto a swift, dreadful death, while if she was innocent it would cause her no harm. The ritual was not an offering for atonement but a means of discovering hidden sin. It applied when a husband suspected impurity but had no direct evidence, and its purpose was to remove suspicion of impurity from Israel. The chapter to which the verse belongs displays God's abhorrence of sin and warns to shun its destructive course and fearful end. The ritual further shows that outward transgression grows from an inward condition of the heart and character.