19 Then the priest will put the woman under oath and say, 'If no man has slept with you and you have not had an adulterous affair and become impure while married to your husband, may this bitter water that delivers a curse not harm you. 20 But if you have had an affair while married to your husband and have defiled yourself by sleeping with a man other than your husband' - 21 here the priest puts the woman under this curse - 'may God cause your people to curse and revile you when he makes your womb shrivel and your belly swell. 22 Let this water that delivers a curse enter your body so that your belly swells and your womb shrivels.' "Then the woman shall say, 'Amen. Amen.'
Matthew Henry's Commentary on Numbers 5:19-22
Commentary on Numbers 5:11-31
(Read Numbers 5:11-31)
This law would make the women of Israel watch against giving cause for suspicion. On the other hand, it would hinder the cruel treatment such suspicions might occasion. It would also hinder the guilty from escaping, and the innocent from coming under just suspicion. When no proof could be brought, the wife was called on to make this solemn appeal to a heart-searching God. No woman, if she were guilty, could say "Amen" to the adjuration, and drink the water after it, unless she disbelieved the truth of God, or defied his justice. The water is called the bitter water, because it caused the curse. Thus sin is called an evil and a bitter thing. Let all that meddle with forbidden pleasures, know that they will be bitterness in the latter end. From the whole learn, 1. Secret sins are known to God, and sometimes are strangely brought to light in this life; and that there is a day coming when God will, by Christ, judge the secrets of men according to the gospel, Romans 2:16. 2 In particular, Whoremongers and adulterers God will surely judge. Though we have not now the waters of jealousy, yet we have God's word, which ought to be as great a terror. Sensual lusts will end in bitterness. 3. God will manifest the innocency of the innocent. The same providence is for good to some, and for hurt to others. And it will answer the purposes which God intends.