Here is the commentary portion:
The Law of Jealousy (Numbers 5)
First, one should note that the passage follows general teaching about confession of sins and appropriate sacrifice for sins (Numbers 5:5–9). This is also the stated goal of the law of jealousy (v. 15). So the law of jealousy flows naturally from the previous teaching about confession of sins.
The stated goal of the law is to bring a woman’s guilt to remembrance (v. 15) if she has committed adultery. In other words, the point of the ritual is to reveal guilt. This is completely characteristic of a trial by ordeal. In Mesopotamian culture, a suspected woman was thrown into a river to see if she would survive. This was practiced in Babylon, Assyria, Elam, Nuzu, Mari, and Carchemish (Roland de Vaux, Ancient Israel, 1:157–58). For example, “If the finger was pointed at the wife of a seignior because of another man, but she was not been caught while lying with the other man, she shall throw herself into the river for the sake of her husband. . . . If that woman did not take care of her person, but has entered the house of another, they shall prove it against that woman and throw her into the water” (Code of Hammurabi 133a; The Ancient Near East: An Anthology of Texts and Pictures, James B. Pritchard, ed. p. 153). If she survived the river, she was deemed innocent of the charge.
The amount of offering is a tenth of an ephah (an omer, a day’s quantity of bread; Exodus 16:16). The same measure was used for the daily grain offering at the tabernacle (Leviticus 6:20) and as a sacrifice for sin for the poor (Leviticus 5:11–13), the latter being the more comparable situation to the offering for jealousy.
THE RITUAL PREAMBLE
The preamble describes what will happen to the woman: (1) she will be brought “before the Lord.” According to Josephus, the rite took place at the temple gate, which was also a public place (Antiquities bk. 3, ch. 11, para. 6) subjecting her to public scrutiny. Mishnah Sotah 1:4 states that the ritual took place at the great court of the temple. (2) The priest will let her hair down, removing its covering, perhaps as a lover might have done (cf. Song of Solomon 4:1; 6:5; 1 Corinthians 11:6). Philo understands this act as symbolizing the laying bare of her soul (Cherubim pt. 1, V, para. 17). (3) She will hold the offering in her hands, which may have held a lover, before a handful is offered to the Lord. (4) She will agree to drink “water of bitterness,” which contains holy water from the bronze laver, tabernacle dust, and ink (v. 23, likely made from carbon/charcoal). (5) She will agree that she should be cursed, if guilty. Each action here is intended to bring intense psychological pressure on an unfaithful woman. The drink has unpleasant features (taste of dust and inky appearance) but would not have the power of a drug. Its power is in the psychological pressure it applies.
Verses 21–22 are curse formulas, wishing or praying punishment upon someone who is guilty. The Old Testament includes numerous examples of such curses. The first part of the curse makes a guilty woman the object of public derision (cf. Jeremiah 24:9; 29:18). The second part of the curse wishes physical harm upon a guilty woman. The language here (occurring nowhere else in the Old Testament) seems intentionally ambiguous, which may enhance its psychological effect so that the woman worries about what will happen to her. Philo understood the curse mildly to mean she would experience loss of pleasure and appetite (Allegorical Interpretation III, LI, 148). Josephus states that her right thigh would be put out of joint and her belly would swell with dropsy/edema. As a result, she would die in a reproachful manner (Antiquities bk. 3, ch. 11, para. 6). Cultural historian Roland De Vaux suggests the curse means that she will be barren forever (Ancient Israel 1:157–58; cf. Deuteronomy 28:17).
THE RITUAL ENACTED
The offering functions as a prayer for the success of the rite. It also costs the husband who brings the accusation—he doesn’t get to do this for free. The amount of the offering is relatively small: an omer, a day’s quantity of bread flour. However, if the husband is wrong about his accusation, he may experience legal penalty (cf. v. 31) such as a sin offering. The shame before the Lord and the community will fall on him.
For the innocent woman, the water does not bring pain and suffering. Why would it? It is just water, dust, and ink. She will go back to her husband under no suspicion and the two shall have children together without him fearing that they belong to another man. Josephus states that the innocent woman would bear a male child in the tenth month after being exonerated! (Antiquities bk. 3, ch. 11, para. 6).
For the guilty woman, the rite causes intense suffering. Having noted the suffering as a sign of guilt, the priest and husband may report her guilt to the people of Israel, who will regard her as accursed. Further penalty is not explicitly stated. It is unlikely that she would be stoned for the adultery since there are insufficient witnesses for such a steep penalty (cf. Numbers 5:13; Deuteronomy 22:13–22). She might be divorced (Deuteronomy 24:1–4) and live apart, barren under the stigma of the curse (Numbers 5:21).
CONCLUDING SUMMARY
Trial by ordeal may seem strange to modern minds but such practices have served in many cultures across time. Benefits of the law and ritual are that they may reveal guilt and bring punishment; they may also exonerate the woman, free her from accusation, and save the marriage.