Sifra and Sifre
Legal midrash on Leviticus, Numbers, and Deuteronomy.
When we hear the word "midrash," we usually think about the rabbinic stories that embellish biblical texts. We might remember the tale about Abraham destroying his father's idols or the story about God prohibiting the angels from rejoicing over the drowning Egyptians. But aside from these narrative midrashim there is a second form of midrash, which concerns itself primarily with legal exegesis. For the sake of simplicity, these two genres are designated as midrash aggadah (narrative midrash) and midrash halakhah (legal midrash). Reality, however, is more complicated--midrash aggadah often includes legal teachings, while midrash halakhah also contains narrative material.
Three of the major collections of midrash halakhah are Sifra--a commentary on the book of Leviticus, and two collections both known as Sifre--one on the book of Numbers and the other on the book of Deuteronomy. The word "sifra" simply means "book" in Aramaic. Traditionally, Jewish schoolchildren began their Torah studies with the book of Leviticus; one text explains this practice by noting that "pure" children are well-suited to study the laws of purity (Vayikra Rabbah 7:3). Whatever the reason for this pedagogical choice, the primacy of Leviticus resulted in its designation as "the book." The major midrashic work on Leviticus also became known as Sifra or "book." The halakhic midrashim on Numbers and Deuteronomy, though two separate works, were often transmitted together. These books therefore became known as "Sifre," or "books."
The legal midrashim on the book of Exodus were probably originally included in the Sifre, but by the Middle Ages, they acquired their own identity as Mekhilta. Because the book of Genesis teaches virtually no laws, there is no collection of midrash halakhah on Genesis. Sifre Zuta (literally: little books) is a collection of midrashim on the book of Numbers. The text of Sifre Zuta was not preserved, and is known to us only through fragments quoted elsewhere. In modern times, scholars have reconstituted and published these fragments as a unified work.
All of these midrashim are line-by-line commentaries that tease laws or clarifications of laws out of the biblical text. Like most midrashim, these texts base their interpretations on puns, attention to unusual words or phrases, and specific interpretive techniques. These techniques include the g'zera shava, an interpretation based on the use of the same word in two places, and ribbui u'miut, which expands the biblical text to apply to any situations not specifically excluded by the verse. Based on the exegetical principle that the Torah contains no superfluous words, the midrashim often derive laws from seemingly unnecessary or difficult words. For example, a midrash on the well-known verse, "Justice, justice shall you pursue in order that you may live and inherit the land that the Lord your God is giving you," begins by explaining the unexpected repetition of the word "justice":