(Bamidbar 5:12) "Speak to the children of Israel and say to them: A man, a man, if his wife go astray, and she be faithless to him": What is the intent of this section? From (Devarim 24:1) "If a man take a woman and he cohabit with her, etc.", we hear only that if he had two witnesses (to her adultery) and she had not been forewarned, that she leaves him by divorce. But if she were adulterous in the presence of only one witness or it is in doubt whether she had or had not been adulterous after having been secreted (with the one she had been forewarned against), we did not hear what is to be done with her.
It is, therefore, written "Speak to the children of Israel and say to them: "A man, a man, if his wife go astray, etc.", that (in the above instance) she must drink the bitter waters. This is the intent of this section. "A man, a man": to include the wife of a deaf mute, an imbecile, one who has gone abroad or been incarcerated, or a dullard — that beth-din forewarns her (if she is deporting herself immodestly) to the end of invalidating her kethubah (her marriage contract).
I might think, even to the end of making her drink (the bitter waters); it is, therefore, written (to negate this) (Ibid. 11) "Then the man shall bring his wife." R. Yossi b. Yehudah says: also to the end of making her drink when her husband is released from incarceration. Variantly: "A man, a man": to include a woman awaiting levirate marriage (yibum). "if his wife go astray": Scripture speaks of those who are fit to be "wives" — to exclude a widow married to a high-priest, a divorcée or a chalutzah (one who has performed the chaliztah ceremony to break a levirate connection), who are married to a regular priest, a mamzereth or a Nethinah (a descendent of the Geveonites) married to an Israelite, and a daughter of an Israelite married to a Nathin or a mamzer.
And, according to Akavya b. Mehallalel, (to exclude) a woman who is a proselyte or a freed slave. They (the sages) said to him (Akavya): But there was a freed slave, Charkemis, in Jerusalem, and Shemaya and Avtalyon had her drink (the bitter waters)! He replied: They dissimulated their doing so — whereupon they excommunicated him and he died in his state of excommunication, and beth-din stoned his coffin. ("if his wife go astray,) and she is guilty of ma'al against him": ("ma'al") In the area of illicit relations or in the area of monetary (fraudulence)? (Ibid. 5:13) "And a man lie with her a lying of seed" indicates that ma'al here is in the area of illicit relations, and not in that of monetary (fraudulence). "and she is guilty of ma'al against him": "me'ilah" in all places is "lying."
And thus is it written (I Chronicles 5:25) "Vayimalu ('and they lied') against the G-d of their fathers," and (Joshua 7:1) "And the children of Israel yimalu ma'al ('falsified') in respect to the ban," and (I Chronicles 10:13) "And Saul died because of his falsification ('bema'alo ma'al') against the L-rd." And, in respect to Uzziyahu, king of Judah, (II Chronicles 26:18) "Leave the sanctuary, for you have acted falsely (ma'alta)," and (Vayikra 5:21) "and he (the denier) ma'ala ma'al against the L-rd" — whence we see that "me'ilah" in all places is "lying."