One of the most unusual passages in the Torah (Bamidbar 5:11-31) concerns the Sotah (wayward wife):
And Hashem spoke to Moshe, saying, “ Speak to the Children of Israel and say to them: Any man whose wife strays, and commits a trespass against him…”

If a woman has been behaving indecently, her husband warns her, in the presence of two witnesses, against any secret meetings with a particular man. Disregarding this, she was observed entering a place with a man where adultery could have occurred. However, there were no witnesses, she was not raped, and she maintains her innocence.

If both she and her husband consent, she is tested with the “bitter waters”. The local court listens to the accusations, and sends two judges as chaperones to accompany her to the Sanhedrin. Throughout, the wife is told that if she will admit her sin, she will be divorced rather than endure the test. In the Sanhedrin she is publicly cautioned, worn down and shamed, so she might recant.

At the eastern gate to the Azara, facing the Holy of Holies, the Kohen administers an oath and curse:
Hashem will make your thigh to fall away and your belly to swell (verse 21),
to which she responds, “Amen, amen.” The whole passage, including Hashem’s Name, is written on parchment. Sanctified water is drawn from the kiyor into an earthenware vessel. Some dirt from the floor of the Sanctuary is strewn on the surface of the water. (In the Temple a marble floor-tile at the northern corner of the altar would be raised to remove the dust.) The passage is dissolved into the water. The Kohen tears the woman’s clothing and loosens her hair. She holds the grain offering in her hands. Then she is made to drink the mixture. The offering is waved, and a portion of it is brought on the altar.

If she is guilty,
“her face turns green, her eyes protrude and her veins swell” (Sotah 20a).
She dies immediately, unless she has merits that delay her death. Her paramour meets a similar death.

But if the woman was not defiled, and she is pure, then she will be unaffected, and she will conceive (verse 28).

The “bitter waters” are effective only if her husband is free of iniquity. Therefore, when adultery became commonplace, R. Yochanan ben-Zakkai discontinued the Sotah ordeal (Sotah 47a-b). Divorce became the only solution.

Although this procedure is unique among the mitzvot – as Ramban says, no other mitzvah depends on a miracle – in a sense, it has precedents. After the sin of the Golden Calf, Moshe
took the calf which they had made and burned it in fire and ground it until it was fine powder. And he scattered it on the surface of the water and made the Children of Israel drink (Shemot 32:20).
He treated them like the Sotah, because idolatry is comparable to adultery:
• …a woman beloved by a paramour, and an adulteress, like the love of Hashem for the Children of Israel, though they turn toward other gods (Hoshea 3:1).
• …for with their idols they have committed adultery (Yechezkel 23:37).
Ibn Ezra says the water revealed who had worshipped the calf. But Rashi (quoting Avoda Zara 44a and Yoma 66b) says the waters actually punished the guilty:
“Three forms of death were administered there: If there were witnesses and warning, by the sword, as is the judgment of the wayward city (Devarim 13:13-18), which were many. If there were witnesses without warning, by plague, as it says, “and Hashem struck the people” (Shemot 32:35). If no witnesses or warning, with dropsy, for the water tested them and their bellies swelled” (Shemot 32:20).

But the origins of the Sotah ordeal go back even earlier. During his plea for Hashem’s justice before destroying Sedom and Amorah,
Avraham spoke up and said, “Behold now I have undertaken to speak to my Lord, but I am dust and ashes” (Bereishit 18:27).
As reward for this expression of humility, Avraham’s descendants
merited two mitzvot: the ashes of the [red] heifer and the dust of the Sotah (Sotah 17a; Chullin 88b; Yalkut Shimoni Vayeira; Bereishit Rabba 49:23).

Maharsha (R. Shmuel Eliezer ben Judah HaLevi Edels, 1555-1631) clarifies that, regardless, the Divine Will would have provided the means for ending impurity caused by contact with death and for determining the suspected wife’s guilt or innocence. However, the processes would have been more difficult. Instead, these transformations can be effected using easily obtainable items  dust and ashes.

The Sotah ordeal is a boon in a sense. As Rashi explains, it establishes justice and prevents mamzerim. If it confirms the wife’s innocence, she will be blessed with conception, malicious talk about her children will cease and family stability (shalom bayit) will be restored.

Etz Yosef (R. Chanoch Zundel ben Yosef, d. 1867) notes further that without the Sotah procedure there might be no alternative but divorce, as is the situation nowadays. As reward for Avraham’s self-abnegation, Sotah holds out the hope for another chance.

Bet Halevi (R. Yosef Dovber ben Yitzchak Zeev Halevi Soloveitchik, 1820-1892) and Maharal (R. Yehudah Loew ben Betzalel, c. 1525-1609) see in Avraham’s “dust and ashes” symbols of the future and the past. Bet Halevi writes:
“Dust never had a significant form, but it can receive a significant form because people can plant in it and grow all flora, or make a useful utensil from it. Ashes had form before, but now one cannot make anything from it, because it was not combinable, nor can it produce vegetation. This is what Avraham said of himself, that he was never important, nor is anything important about to come from him. … The ashes of the [red] heifer purify the defiled one from now into the future, while the dust of the Sotah makes clear that all along she was undefiled. Both of them are measure for measure.”

At times we are surprised to discover, concealed within our individual pain, Hashem’s nearness, encouragement and love.