The Talmud is the most comprehensive compilation of the Oral Law. Throughout its many volumes, one finds the rabbis engaged in two types of discussions, halakha (purely legal matters), and aggadata (ethical and folkloristic speculations).

The opening Mishna in the tractate Bava Mezia is a classic halakhic discussion:

"Two men are holding a cloak [and come before a judge]. This one says: 'I found it,' and the other one says, 'I found it.' If this one says, 'It is all mine,' and the other one says, 'It is all mine,' then this one must swear that he does not own less than a half, and the other must swear that he does not own less than a half and they divide it [dividing means that each gets half of the value of the cloak].

"If this one says: 'It is all mine,' and the other one says, 'It is half mine' [because he believes that they discovered it simultaneously then the one who says, 'It is all mine' must swear that he does not own less than three quarters, and the one who says, 'Half of it is mine' must swear that he does not own less than a quarter, and this one takes three quarters and this one takes one quarter."

The Talmud's discussion of this Mishna is very extensive, and directly and indirectly raises numerous legal nuances. For one thing, since each party concedes that he only found the cloak but never purchased it, what about the man to whom the cloak originally belonged-shouldn't it be returned to him? We must assume, therefore, that the cloak either had been abandoned or that efforts to find the owner had proven futile. (There are extensive laws in the Talmud dealing with restoring lost objects to their owners, based on the biblical laws recorded in Deuteronomy 22:13.)

Secondly, it is no coincidence that the Mishna portrays both parties coming into court holding the cloak. As a rule, Jewish law accepts the principle that "possession is nine tenths of the law." In noting that both litigants are holding the garment, the text underscores that each has a tangible claim. If, in fact, only one party held the cloak, the cloak would be presumed to belong to him unless the second litigant could produce evidence that the first person had taken it from him.

Third, why the need for an oath at all? Why not just divide the cloak? The purpose of the oath is to induce fear in the liar, to discourage him from persevering in his dishonesty. Without an oath, a person might be more prone to lie, feeling that no harm is involved, since he is not depriving the real finder of something that had cost him money, but only of something he had found. Rabbi Louis Jacobs summarizes the principle behind the oath: "While a man may be willing to tell an untruth in order to obtain something that is not his, he will be reluctant to swear in court that he is telling the truth when he is not really doing so." In Jewish law, perjury is a particularly serious sin, and outlawed by the ninth of the Ten Commandments.

Fourth, why do the rabbis impose so strange an oath? Since each litigant claims "it is all mine," why not have each one swear that the entire cloak belongs to him? What is the sense in saying "I swear that I own not less than a half." There is a moral consideration behind the strange wording. Were each party to swear to owning the entire garment, the court knowingly would be administering a false oath: Two people would be swearing to full ownership of one garment. Yet were each party to swear that he owns only half of the garment, he would be discrediting his earlier claim that he owns it all. That is why each party swears, "I own not less than a half." This is the only oath that might possibly be truthful, for the two litigants might have picked up the garment simultaneously.

As for the Mishna's second part — in which one party claims ownership of the whole garment, and the other ownership of half — why the strange wording of the oath, and why give one litigant three quarters of the garment's value and the other only one quarter? The Talmud reasons: Since the person who claims that he owns only a half admits that the other half of the garment belongs to the first litigant, the dispute facing the court is restricted to the remaining half. That half, the court in turn divides in half, so that one party gets three quarters and the other a quarter.

This lengthy discussion about halves reminds me of an old Jewish joke about a man who complains to his friend, "A horrible thing. My daughter is getting married tomorrow and I promised a five-thousand ruble dowry. Now, half the dowry is missing."

"Don't worry," his friend consoles him. "Everybody knows that people usually pay only half the promised dowry."

"That's the half that's missing."

Aggadata refers to all of the Talmud's nonlegal discussions, including such varied matters as medical advice, historical anecdotes, moral exhortations, and folklore. One particularly well-known bit of aggadata is found in the talmudic tractate Bava Mezia 59b. The aggadata follows a halakhic discussion in which the rabbis debated whether an oven that had become impure could be purified. While almost all the sages felt it couldn't be, Rabbi Eliezer, a lone voice but a great scholar, disagreed:

"On that day, Rabbi Eliezer put forward all the arguments in the world, but the Sages did not accept them.

"Finally, he said to them, 'If the halakha is according to me, let that carobtree prove it.'

"He pointed to a nearby carob-tree, which then moved from its place a hundred cubits, and some say, four hundred cubits. They said to him 'One cannot bring a proof from the moving of a carob-tree.'

"Said Rabbi Eliezer, 'If the halakha is according to me, may that stream of water prove it.'

"The stream of water then turned and flowed in the opposite direction.

"They said to him, 'One cannot bring a proof from the behavior of a stream of water.'

"Said Rabbi Eliezer, 'If the halakha is according to me, may the walls of the House of Study prove it.'

"The walls of the House of Study began to bend inward. Rabbi Joshua then rose up and rebuked the walls of the House of Study, 'If the students of the Wise argue with one another in halakha," he said, "what right have you to interfere?'

"In honor of Rabbi Joshua, the walls ceased to bend inward; but in honor of Rabbi Eliezer, they did not straighten up, and they remain bent to this day.

"Then, said Rabbi Eliezer to the Sages, 'If the halakhah is according to me, may a proof come from Heaven.'

"Then a heavenly voice went forth and said, 'What have you to do with Rabbi Eliezer? The halakhah is according to him in every place.'

"Then Rabbi Joshua rose up on his feet, and said, 'It is not in the heavens' (Deuteronomy 30:12).

"What did he mean by quoting this? Said Rabbi Jeremiah, 'He meant that since the Torah has been given already on Mount Sinai, we do not pay attention to a heavenly voice, for You have written in Your Torah, 'Decide according to the majority' (Exodus 23:2).

"Rabbi Nathan met the prophet Elijah. He asked him, 'What was the Holy One, Blessed be He, doing in that hour?'

"Said Elijah, 'He was laughing and saying, "My children have defeated me, my children have defeated me.""'

The British-Jewish scholar and writer Hyam Maccoby has commented: "This extraordinary story strikes the keynote of the Talmud. God is a good father who wants His children to grow up and achieve independence. He has given them His Torah, but now wants them to develop it...."

A third category of rabbinic literature is midrash, of which there are two types. Midrash aggada derive the sermonic implications from the biblical text; Midrash halakha derive laws from it. When people use the word midrash, they usually mean those of the sermonic kind. Because the rabbis believed that every word in the Torah is from God, no words were regarded as superfluous. When they came upon a word or expression that seemed superfluous, they sought to understand what new idea or nuance the Bible wished to convey by using it. Thus, we find the following discussion on a verse from Genesis concerning Noah.

"This is the story of Noah. Noah was a righteous and blameless man in his generation" (Genesis 6:9).

What words seem superfluous? "In his generation." So why, the rabbis ask, did the Torah include them?

Characteristically, more than one view is offered. Rabbi Yochanan said: "In his [particularly awful] generation [Noah was a righteous and blameless man] but not in other generations." Resh Lakish maintained: "[If even] in his generation' how much more so in other generations" (Sanhedrin 1 08a).

Aside from the ingenuity of these explanations, this midrash also demonstrates that a reader understands a text in light of his own experiences. Take Resh Lakish's point: If even in his generation Noah was righteous, how much more so would he have been had he lived in another society? Elsewhere, the Talmud informs us that Resh Lakish became religious only as an adult. Earlier on, he had been a thief, a gladiator, or a circus attendant. Resh Lakish knew firsthand how much harder it is to be a good person when you come out of a seedy or immoral environment. In his eyes, if Noah could emerge from so immoral a society as a righteous man, how much greater would he have been had he been raised among moral people.

Midrash continues to be created. For example, Genesis 19:26 records that when Lot and his family were fleeing the destruction that God wrought on Sodom and Gomorrah, they were told not to look back. "But Lot's wife looked back, and she thereupon turned into a pillar of salt."

What possible relevance could this verse have to our lives? A friend of mine was teaching this chapter at a home for the aged, and the residents were debating the verse's meaning. An eighty-five-year-old woman broke into the discussion: "Don't you understand what it means? When you are always looking backwards, you become inorganic."

Finally, in modern Jewish life, the word halakha refers to any issue of Jewish law. If a person wants to know the Jewish law on a specific issue, he will ask a rabbi, "What is the halakha in this case?" The word also is used for the Talmud's legal sections, the codes of Jewish law (for example, the Shulkhan Arukh) or any of Judaism's legal writings (e.g., Responsa).

Aggadata, as noted, describes the non-halakhic sections of the Talmud, and the word aggada in modern Hebrew refers to any legendary or folkloristic writing.

Midrash most commonly refers to the famous compilation of Midrash Rabbah, a compilation of the rabbis' comments on each of the five volumes of the Torah. But to this day, you can hear a Jew who has some novel interpretation of a Torah passage say, "I want to give you a drash [from midrash] on this week's Torah portion."

Sources: Joseph Telushkin. Jewish Literacy: The Most Important Things to Know About the Jewish Religion, Its People and Its History. NY: William Morrow and Co., 1991. Reprinted by permission of the author.

Jewish Holy Scriptures: Halakha/Aggadata/Midrash