A man suspected of an adulterous relationship with a married woman went into hiding in her home when her husband unexpectedly entered. From his place of concealment he saw the husband about to eat from some food which had been poisoned by the venom of a snake that had bitten into it. He called out a warning to him to save him from being fatally poisoned. His revelation of his presence, however, aroused suspicion that he had been illicitly involved with the woman of the house, and thus rendered her forbidden to her husband.

When the case came before the Sage Rava he ruled that the woman could remain married to her husband because it could be assumed that her suspected paramour was not guilty of adultery. His reasoning was that if this fellow was indeed involved in such a relationship he would have preferred to let the husband die from eating the poisoned food so that he could then marry the widow. He even cited a passage (Yechezkel 23:45) to the effect that adulterers are suspect of even murdering the man who stands in their way.

To the gemara's challenge that this is an obvious deduction not worthy of mention the answer is given that if not for Rava's ruling there would be grounds for assuming that the suspect had indeed committed adultery. But why then would he be interested in keeping the husband alive? Because, as King Solomon says (Mishlei 9:17), "Stolen waters are sweet and secret bread is pleasant." This consideration might have provided a motive for an adulterer to keep the husband alive so that he would continue to indulge in the illicit pleasure of "stolen waters."

Despite this possibility Rava definitively concluded that this had not been the motive of the suspect. Tosefot writes that an adulterer is not aware of Solomon's insight into human nature regarding the sweetness of stolen waters. This is explained by Rabbi Eliyahu Dessler in the following manner:

Man deludes himself into thinking that finding a legal and simple way to enjoy a forbidden pleasure will bring him the gratification he seeks. In truth, however, the goal of uncontrolled desire is to be free of restraints. Should a sinner fully realize that this is so, he would cease his search for them. If the suspect was really an adulterer he would be unaware of the "stolen water" motive at the root of his behavior and would opt to see the husband die. Since he intervened, Rava concluded that nothing illicit had been perpetrated.

"Remember the Shabbat," says the Torah, "to keep it holy." How do we remember the Shabbat? The gemara (Mesechta Pesachim 106a) informs us that this is done by making kiddush over wine. The obligation to say a blessing declaring the sanctity of the Shabbat is unquestionably of Torah origin, but is the need for doing this over wine also a Torah requirement, or is it of rabbinical origin?

This is the subject of a debate between the commentary presumed to be Rashi and the commentary of Tosefot in our gemara. Their debate focuses on the gemara's discussion of whether a nazir who is forbidden to drink wine may drink the wine of kiddush. Rashi's understanding of the gemara is that the need to make kiddush over wine is of Torah origin and therefore the vow to abstain from that wine cannot take effect. Tosefot, on the other hand, contends that the wine part of the kiddush is only of rabbinical origin, so that the vow takes effect and makes that wine forbidden to him.

In explaining why there is a need for making kiddush over wine, the Sefer Hachinuch points out that it is human nature to be stimulated by wine which causes both satiety and joy (Mesechta Berachot 35b). Where wine is not available, kiddush can be said over bread because the satisfaction of his hunger can also be a source of stimulation.

Since most authorities agree with Tosefot's opinion that the Torah obligation is fulfilled with words alone, it would seem that one who says the ma'ariv service on Shabbat Eve has already discharged his Torah obligation and his need to make kiddush at home on wine is only of rabbinical origin. This is indeed the position of Magen Avraham (Shulchan Aruch Orach Chaim 271:1) who discusses an interesting ramification regarding making kiddush for women who have not prayed ma'ariv. Mishnah Berurah (ibid.) takes sharp issue with his approach and concludes that one does not fulfill the Torah mitzvah of kiddush until he says it over wine before his Shabbat Eve meal.

There is one occasion, however, for relying on the ma'ariv service for kiddush. This is when Yom Kippur is on Shabbat and kiddush is not made on wine. Some authorities therefore advise having in mind in the ma'ariv of Shabbat Yom Kippur to fulfill with that service the mitzvah of kiddush.