What is shatnez, and what materials does it cover?

Shatnez is the prohibition on wearing a garment that blends wool (from sheep) and linen (from flax) through spinning, weaving, or felting. No other fiber combinations are covered — cotton-polyester blends, silk-wool, etc., are not shatnez. The specific wool-linen combination is the Torah's concern, possibly because these are the two primary natural fibers of ancient Israel's textile industry and the combination was well-known.

What does it take for a garment to constitute shatnez?

The fibers must be structurally integrated — spun, woven, or felted together. The Talmud (Kilayim 9:1) rules that simply having both materials present in a garment is not enough. But the Mishnah (Kilayim 9:8) adds that even stitching a linen patch with a wool thread violates shatnez. Modern shatnez testing checks every component: labels, interfacing, padding, stitching, and backing, not only the main fabric.

How can the high priest wear garments that would otherwise constitute shatnez?

The Talmud (Yoma 69a) explains that kilayim prohibitions operate in the profane realm — the ordinary world of everyday clothing. The holy realm (the Temple, divine service) is governed by different principles. What is forbidden in ordinary life may not only be permitted but commanded in sacred service. The high priest's shatnez garments are not an exception that undermines the rule; they express the rule's scope: the boundary applies where the ordinary operates, not in the sacred.

Why is shatnez called a chok (statute without reason)?

Deuteronomy 22:11 gives no explanation — unlike commandments that state “because you were slaves in Egypt” or “because the LORD is one.” The Talmud (Yoma 67b) includes shatnez among the chukim that the nations mock: “What impurity is there in shatnez? What sin is there in eating pork?” The answer is not rational justification but divine command. Observing a chok is an act of submission to divine authority that transcends personal understanding.

What does the shatnez prohibition's survival in modern times — including shatnez laboratories — reveal about halachic observance?

The commandment is observed in its technical detail — not as a metaphor or principle but as a practical fiber-by-fiber check of every garment. The existence of shatnez laboratories using microscopy to test modern clothing illustrates that halachic observance takes the specificity of Torah commands seriously. “You shall not wear wool and linen together” means checking your suit jacket's internal stitching, not merely avoiding obviously mixed garments.

Commandment #199 · Negative · Purity Laws

Wool and Linen Together: The Prohibition of Shatnez

שַׁעַטְנֵז

Source: Deuteronomy 22:11 · Maimonides, Laws of Kilayim 10:1

Commandment #198 covered kilayim (mixed species) broadly. Commandment #199 focuses specifically on shatnez — the prohibition in Deuteronomy 22:11 against wearing a garment of wool and linen together. The Leviticus 19:19 parallel uses the word “shatnez” (from a root meaning “combed, spun, woven”) to describe the forbidden combination. The prohibition applies only to wool (from sheep) and linen (from flax) — not other fiber combinations. A garment with both fibers must be checked; Jewish law still requires testing by certified shatnez laboratories before wearing certain garments.

Wool and Linen: What Constitutes Shatnez

לֹא תִלְבַּשׁ שַׁעַטְנֵז צֶמֶר וּפִשְׁתִּים יַחְדָּו

"You shall not wear a garment of different sorts, such as wool and linen together."

Deuteronomy 22:11 — Open in Torah Reader

The Talmud (Kilayim 9:1–10) and Mishnah define shatnez as a garment in which wool and linen are both present through one of three methods: spun together, woven together, or felted together. Simply having both fibers present is not enough — they must be structurally integrated. The Mishnah (Kilayim 9:8) rules that stitching a linen patch with a wool thread (or vice versa) violates shatnez. The prohibition applies to wearing — carrying or using a shatnez garment for other purposes (e.g., as a blanket you sit on without wearing) is debated.

The Talmud (Kilayim 9:2) also asks: what about garments with labels or stuffing? If a wool garment has a small amount of linen in its label, does that constitute shatnez? The ruling is that the label must be removed if it is of the prohibited fiber combination. The modern shatnez laboratory tests every part of a garment.

The High Priest's Exception: Shatnez in the Holy

The most striking dimension of shatnez is its exception: the high priest's garments explicitly contained both wool and linen — the ephod, the breastplate, the robe were all wool; the linen tunic was linen; and they were worn together. The Talmud (Yoma 69a) notes this apparent contradiction: shatnez is forbidden to Israelites, yet the most sacred service in Israel is performed in what would otherwise be shatnez. The resolution: kilayim prohibitions apply in the profane realm; the sacred realm operates by different rules — what is forbidden in ordinary life may be commanded in divine service. The high priest's garments are not merely permitted shatnez; they may be a statement that the divine realm transcends the ordinary categories that apply to human life.

Exodus 28:6 records the ephod — the high-priestly garment that combines wool and linen together — as a divine command, showing that the same God who prohibited shatnez in ordinary dress commanded it in the holy service.

Key Figures

The Shatnez Laboratory

Today, certified shatnez laboratories use microscopy to test garments at the fiber level — identifying wool proteins and linen fibers that may be present in labels, interfacing, padding, or stitching invisible to the naked eye. Designer suits frequently fail shatnez testing because their labels or internal structures use the wrong fiber combination. The existence of a modern scientific profession dedicated to implementing a biblical statute with precision illustrates how Deuteronomy 22:11's chok continues to be observed in its technical detail two millennia after the Temple's destruction.

The Garment of Adam and Eve

Genesis 3:21: “The LORD God made for Adam and for his wife garments of skins and clothed them.” The first act of clothing is divine — God provides the garment. The tradition of careful attention to what covers the human body — from God's garment-making in Eden to the shatnez prohibition's detailed fiber regulations — reflects a consistent Torah concern with the holiness of the physical body and what it wears. The garment touches the divine image; what touches the divine image matters.

Study Questions

For reflection and group study

What are the three methods of fiber integration that constitute shatnez — and why does the mere presence of both fibers in a garment not automatically make it forbidden?

Why are the high priest's garments an exception to the shatnez prohibition — and what does this exception reveal about the relationship between the holy and the ordinary in Torah law?

Why is shatnez classified as a chok (statute without a stated reason), and how does this classification affect how Jews relate to the commandment?

What is the modern shatnez laboratory — and what does its existence reveal about how technical statutes are observed in practice today?

How does the Torah's concern for the composition of garments connect to a broader theology of holiness applied to the physical body?

Read the full passage in the Torah reader.

Open Deuteronomy 22 in the Bible Reader

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