Musar do Liczb 26:7

A person has to conduct himself at all times in such a way that he does not arouse the suspicion of transgressing laws either vis-a-vis G–d or vis-a-vis his fellow man. The example of the Sotah teaches this lesson, since she had to undergo public embarrassment in order to prove her innocence. The Zohar there says that the whole of Israel was treated in a like manner by Moses at Marah. When the Israelites came out of Egypt and they came to Marah and found the water unfit to drink they were given the kind of מים המאררים that one gives to a woman suspected of unproven marital infidelity. All the Egyptians had been saying that the children of the Israelites who left Egypt were in reality the offspring of Egyptians who had slept with Jewish women. As a result of such accusations a number of Jewish husbands suspected their wives of infidelities committed in Egypt. Also Jewish wives suspected their husbands of infidelities committed with Egyptian women. This is why G–d told Moses to examine the truth of these accusations by means of these waters, to eliminate unfounded suspicions. After that episode G–d gave them חוק ומשפט ושם נסהו, "there He gave them statutes and social laws, and there He examined them" (Exodus 15,25). The Torah attests to this by calling the tribes “שבטי י-ה עדות לישראל” that all these accusations had been unfounded. An allusion to this can be found in our verses in the peculiar description of the tribes as הראובני, השמעוני, etc, instead of ראובן, שמעון, etc. The extra letters ה and י, spell the two lettered name of G–d, י-ה, and indicate that all the tribes were pure, no one had committed any infidelity, otherwise the Torah would not bestow this compliment on them. When the Priest examines the Sotah in our paragraph, the purpose is similar to that of Moses at the time.

Then he should recite as he stands by the doorway beside the mezuzah in his tallis and tefillin: “Hear, O Israel, Hashem is our God, Hashem is one. O Unique and Unitary One, unify my heart to love and fear Your great, mighty and awesome Name with all my heart and soul.” Afterwards he should recite the eight verse beginning with the letter hei in Tehillim, Chapter 119 (verses 33-40). Then he should recite Mishlei 18:10, “The name of Hashem is a mighty tower, the righteous man runs into it and is protected.” And Tehillim 122:4: “The tribes of God, as a testimony for Israel to give thanks the Name of Hashem.” You recite eight verses of Tehillim 119 because they begin with the letter hei and end with the letter yud, spelling out the Name Y-h, which is the Name that served as testimony to the purity of the tribes of Israel in Egypt, as it is stated HaReuveiny (Bamidbar 26:7). [That is, when the families of Israel are listed in that passage a hei is appended to the beginning of each name and a yud to the end of each name, indicating that Hashem Himself attested to their purity].