Halakhah do Liczb 5:12

That is that He commanded us about the law of the sotah (suspected adulteress). And that is His, may He be blessed, saying, "if a man’s wife has gone astray" (Numbers 5:12). And the regulations of this commandment - how she is made to drink, how she offers her sacrifice and her [other] stipulations besides this - have all already been explained in Tractate Sotah. (See Parashat Nasso; Mishneh Torah, Woman Suspected of Infidelity 3)

The commandment of the suspected adulteress (sotah) for the husband to bring her to the priest and that he do to her according to the statute that is written: To bring the sotah woman to the priest, so that he do to her according to the statute that is written about her in the [relevant] section of the Torah. And the matter of the sotah is explained in Scripture - that she is a woman whose husband has become jealous about her. And they, may their memory be blessed, have already explained (Midrash Tanchuma, Nasso 5) what is [the meaning of] the expression, sotah, [that it is] meaning to say, she wandered from her husband - as most jealousy comes from the reason of the woman's licentiousness. And hence she is called a "sotah from her husband," since he is jealous about her. And the Scripture that teaches about this commandment is "If any man's wife stray, etc. And he shall bring his wife to the priest" (Numbers 5:12-15).