A bold interpretation of the verse “do not cook a kid in its mother’s milk,” from medieval commentator Bekhor Shor (12 th cent. CE) leads to an intriguing academic explanation of inner-biblical exegesis charting the development of the mitzvah.

Judaism as we know it forbids Jews 1) to cook meat and milk together, 2) to eat meat that was cooked with milk, 3) to receive any benefit from such a concoction. Yet, there is no mention of these prohibitions in the Torah. Where did this prohibition come from? The Rabbis derive this prohibition from the phrase[1] לא תבשל גדי בחלב אמו generally translated as “do not cook a kid in its mother’s milk,” which appears a total of 3 times in the Torah (Exodus 23:19, & 34:26 and Deuteronomy 14:21). But to be sure, there is little in the verse that would suggest anything beyond literally cooking a kid in its mother’s milk.

The parameters for this rule are unclear. Chazal (the Sages) debate to which animals this law applies. The verse only refers to goats, but the positions in the Mishna range from domesticated kosher mammals (R. Akiva), all kosher mammals (R. Yossi HaGelili) or all kosher animals other than fish and grasshoppers (Tanna Kamma and Rav Yosef).[2] Although Rabbi Akiva admits that wild animals and birds fall into this prohibition as a matter of rabbinic law (though not Torah law), Rabbi Yossi Ha-Gelili remained staunch that the prohibition does not extend to birds, since they have no mother’s milk, and in his town chicken parmesan would have been served at his own table (b. Shabbat 130a).

The Rabbis debate other matters as well, such as whether there should be a waiting period between meat and milk, whether separate dishes are required, etc.[3] However it all begins with the three verses in the Torah, and it is to these verses which I now turn.

What does this Phrase Mean in Exodus?

The phrase, “do not boil a kid in its mother’s milk” is an enigma. Why would somebody do this? Rambam, in his Guide of the Perplexed (111:48), suggested that this could have been a pagan ritual, but there is no evidence for this.[4] So what does it mean? Looking at the context in which the phrase is used only makes the problem worse. Even a cursory read shows that it seems disconnected from the verse in which it is found.

Here is the passage as it appears in Exodus 23:

יח לֹא תִזְבַּח עַל חָמֵץ דַּם זִבְחִי וְלֹא יָלִין חֵלֶב חַגִּי עַד בֹּקֶר. יט רֵאשִׁית בִּכּוּרֵי אַדְמָתְךָ תָּבִיא בֵּית יְהוָה אֱלֹהֶיךָ לֹא תְבַשֵּׁל גְּדִי בַּחֲלֵב אִמּוֹ.

18 You shall not offer the blood of My sacrifice with anything leavened; and the fat of My festal offering shall not be left lying until morning. 19 The choice first fruits of your soil you shall bring to the house of Yhwh your God.You shall not boil a kid in its mother’s milk(NJPS with adaptations).

The text in Exodus 34 is virtually identical.[5]

כה לֹא תִשְׁחַט עַל חָמֵץ דַּם זִבְחִי וְלֹא יָלִין לַבֹּקֶר זֶבַח חַג הַפָּסַח. כו רֵאשִׁית בִּכּוּרֵי אַדְמָתְךָ תָּבִיא בֵּית יְהוָה אֱלֹהֶיךָ לֹא תְבַשֵּׁל גְּדִי בַּחֲלֵב אִמּוֹ.

25 You shall not offer the blood of My sacrifice with anything leavened; and the sacrifice of the Feast of Passover shall not be left lying until morning. 26 The choice first fruits of your soil you shall bring to the house of Yhwh your God. You shall not boil a kid in its mother’s milk.

In both cases, the phrase seems like an addendum. Even so, why was it put here of all places? What does boiling a kid in its mother’s milk have to do with sacrifices or first fruit offerings?

Most traditional commentaries ignore this problem entirely and focus on the traditional explanation of the passage, the prohibition of cooking and consuming meat and milk together. Some commentaries with a peshat orientation, like Rashbam and ibn Ezra, attempt to find some connection between the prohibition and its context.

The most radical interpretation, and one which takes the context of the verse as paramount, is that of R. Joseph ben Isaac Bekhor Shor (12th cent., Orleans). He believes that the phrase as its classically understood is a mistranslation. In fact, Bekhor Shor argues, the verse has nothing to do with cooking a kid in its mother’s milk or with cooking milk and meat together. He writes:

לפי הפשט, “בישול” לשון גידול וגמר, כמו “הבשילו אשכלותיה ענבים.” והכי קאמר: לא תניחנו לגדל ולגמול בחלב אמו, שתאחרנו עד שתגדלנו האם בחלבה, אלא בראשית תביאנו, דומיית תחילת הפסוק שאמר: “ראשית בכורי אדמתך.”

According to the plain meaning, the term “bishul” here means grow or complete, similar to its use [in the verse (Gen. 40:10)]: “its clusters ripened (הבשילו) into grapes.” This is what the verse is saying: do not allow [the kid] to grow up and be weaned from its mothers milk. [In other words, do not] wait until [the kid]’s mother grows it with her milk, rather bring it at the beginning. This fits with the context of the first part of the verse, “the choice first fruits of your soil [you shall bring].”

Again, in Exodus 34, Bekhor Shor offers a virtually identical interpretation.

לפי הפשט: לא תעזבנו עד שיגמור גידולו בחלב אמו, ”בישול“ משמע גמר, כמו ”הבשילו אשכלותיה ענבים.“ וכן בלשון תלמוד ”[ארץ ישראל] קלה לבשל פירותיה.“ והוא דומיא דרישא דקרא, ”ראשית בכורי אדמתך,“ משמע שמתבכרות, שלא תאחר עד גמר הפירות.

According to the plain meaning, to not leave [the kid] until it is full grown from its mother’s milk. “Bishul” implies completion, as [in the verse (Gen. 40:10)]: “its clusters ripened (הבשילו) into grapes.” The Talmud uses the term similarly (b. Ketubot 112a): “[The land of Israel] grows its fruit with ease.” This makes it of a piece with the beginning of the verse “the choice first fruits of your soil [you shall bring].” This implies that they are going through the process of maturation,[6] that one should not delay until the fruits are all ripe.

According to this reading, the phrase לא תבשל גדי בחלב אמו has nothing whatsoever to do with eating meat or even cooking it. Instead, the phrase should be understood as a poetic way of expressing the requirement to bring the first-born animals to God as soon as possible. Not only does this read very well in the context of v. 19, as Bekhor Shor points out, but it even fits well with the theme in v. 18. In that verse, the Torah commands Israel not to leave over the fat of the sacrifice until morning but to eat the entire sacrifice that evening, at the proper time. In other words, the entire unit of vv. 18-19 is about being punctual about doing God’s service and not waiting or leaving things for later.

What does this Phrase Mean in Deuteronomy?

The context of the verse in Deuteronomy is very different. The phrase appears as part of a list of forbidden foods, specifically, the prohibition of eating non-slaughtered meat. This forces the reader to search for a different translation; since the phrase is not part of a discussion of first fruits, Bekhor Shor’s translation of the text does not work here. The text in Deuteronomy reads:

כא לֹא תֹאכְלוּ כָל נְבֵלָה לַגֵּר אֲשֶׁר בִּשְׁעָרֶיךָ תִּתְּנֶנָּה וַאֲכָלָהּ אוֹ מָכֹר לְנָכְרִי כִּי עַם קָדוֹשׁ אַתָּה לַיהוָה אֱלֹהֶיךָ לֹא תְבַשֵּׁל גְּדִי בַּחֲלֵב אִמּוֹ.

21 You shall not eat anything that has died a natural death; give it to the stranger in your community to eat, or you may sell it to a foreigner. For you are a people consecrated to Yhwh your God. You shall not boil a kid in its mother’s milk.

Bekhor Shor himself notices the changed context and gives a very different explanation for the phrase here.

בשר בחלב אסור לבשל, דרך בישול אסרה תורה… ואסור בשר בחלב באכילה והנאה, מדכתיב תלתא “לא תבשל” בתורה. ו”אמו” נתינת טעם, דדרך אכזריות שיבשל בשר בחלב [האם] שגידלתו, והבהמה שיצא ממנה החלב שמא אמו הייתה… וזאת המצוה דומיא ד”לא תקח האם על הבנים” ו”אותו ואת בנו.”

It is forbidden to cook meat in milk. The Torah specifically forbids the cooking… It is also forbidden to eat or derive any benefit from meat [cooked] in milk. The inclusion of the term “its mother” comes to teach us the reason [for the law], for it would be cruelty to cook the flesh of a kid in the milk of [the mother] which raised it. [Therefore, all milk is forbidden,] for perhaps the animal from which this milk came was its mother… This mitzvah is similar to “do not take a mother[-bird] with its chicks” and “an animal and its offspring [should not be slaughtered in one day].”

Here Bekhor Shor makes a 180˚ turn. Like the Rabbis, he understands this passage to be speaking about cooking meat in milk. He even adds the Rabbinic midrash about milk and meat being forbidden to eat and to derive benefit from, a midrash that is itself based upon all three verses. To some extent, this is not surprising. Like Rashbam before him, Bekhor Shor believes that there is a place for midrash, even when it contradicts peshat. Midrash is what undergirds halacha.

Nevertheless, Bekhor Shor makes a strong point. There is a peshat element that cannot be ignored. The passage in Deuteronomy seems to be associating this rule with the rules of forbidden foods. It seems only logical to offer a reading of the prohibition in this phrase that would end with some sort of forbidden food item.[7]

How can One Phrase Mean Two Different Things? An Academic Explanation

Bekhor Shor’s explanation of the verses in Exodus is persuasive, at least to me, but so is his point that the verse in Deuteronomy is about a food prohibition. How can the same phrase mean two totally different things in the same book, the Torah? This is a question that Bekhor Shor does not tackle, but it is one uniquely suited to the academic assumption that the Torah has layers, and is made up of a number of different sources, which were written over a long period of time and eventually put together by a later editor.

Most scholars believe that the author of the Deuteronomy (D) was familiar with the Covenant Collection (the academic term for the laws in Exod. 20:19-23:19) and used it as a basis from which to compose his own work.[8] Since the source for the original law of the kid and its mother’s milk comes from the (earlier) Covenant collection, the following timeline suggests itself.[9]

The Covenant Collection presents a discussion of the requirement to bring first fruits and firstborn animals to God (probably at a local sanctuary—see Exodus 20:24 [Eng. 21]). The requirement was phrased in a poetic manner, with the unusual idiom, “do not let the kid grow fat on its mother’s milk.” When the author of the Deuteronomic Code was reading this work, he understood the phrase literally, as “do not boil a kid in its mother’s milk,” and, therefore, combined it with the list of prohibited animals—an example of what Michael Fishbane calls, inner-biblical exegesis.[10]

If the timeline I suggested is correct, then it was not the Rabbis who began the process of creating the law forbidding meat and milk cooked together, but the Deuteronomist, the biblical author of D, who began this process by reinterpreting the original law and giving it a whole new meaning. The verse in Deuteronomy may still be a long way from milchig and fleischig sinks, but it is the first step.