The 262nd prohibition is that one who purchases a Jewish maidservant and then marries her is forbidden from afflicting her. When I say "from afflicting her," I mean that he may not diminish her food, clothing, or conjugal rights (sh'eirah, k'susah, onasah) with the intention of afflicting her and causing her anguish.
The source of this commandment is G‑d's statement1 (exalted be He), "He may not diminish her food, clothing, or conjugal rights."
This same prohibition also applies to one who has married any Jewish woman; he also is prohibited from afflicting her in any of these three areas, with the intention of causing her anguish and distress.
The source for this is G‑d's statement2 (exalted be He) regarding the Jewish maidservant [whose master marries her and] whose food, clothing, and conjugal rights may not be withheld, "She must be treated exactly as other [married] women." From here we learn that the [proper] treatment of all married women is that one may not diminish their food, clothing, and conjugal rights.
Our Sages explained this in the Mechilta: "What does the verse, '[She must be treated] exactly as other [married] women' teach us [about the treatment of the maidservant]? It appears to come here to teach us something; but rather it ends up being taught about."3
There it is also explained that sh'eirah refers to food; k'susah is meant literally [i.e. clothing], and onasah refers to conjugal rights.
