Kashering Knives: Lessons From the War with Midian
Parsha Halacha – Parshat Matot – Masei
Shabbat Chazak / Shabbat Mevarchim Menachem Av
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The Torah portion of Matot (Masei) recounts the war between the Jewish people and the Midianites.
After the soldiers returned from battle, Moshe was angry that they had spared the women despite the fact that those very women had enticed the Jewish men to sin. He therefore gave instruction that the women be killed and that only the children be spared. After this Elazar, the Kohen Gadol, instructed the soldiers how to kasher the utensils they had taken as spoils of war. As the Torah says (Numbers 31:21-23),
וַיֹּאמֶר אֶלְעָזָר הַכֹּהֵן אֶל אַנְשֵׁי הַצָּבָא הַבָּאִים לַמִּלְחָמָה זֹאת חֻקַּת הַתּוֹרָה אֲשֶׁר צִוָּה ה׳ אֶת מֹשֶׁה
“Elazar, the priest, said to the troops who had taken part in the fighting, ‘This is the ritual law that the L-rd has enjoined upon Moses.’”
Coming to War
The words הַבָּאִים לַמִּלְחָמָה would normally be translated as “who were coming to war.” This is unusual since the soldiers Elazar was addressing had just returned from war and were coming home.
The Battle Begins After the War
The Chovot HaLevavot (beginning of chapter 5 of Sha’ar Yichud HaMa’ase, quoted in Pardes Yosef) brings the following anecdote which can be used to explain the verse: A group of soldiers were returning from a fierce battle laden with their spoils of war. They were greeted by a pious man who said to them, “You have completed a small battle and have arrived with your spoils, now prepare yourselves for a great battle.” “What is the great battle?” they queried.
He explained, “The battle with the yetzer hara (evil inclination) and his agents! (I.e., with your newfound wealth you will have many temptations to sin.) In an ordinary battle, the enemy will give up after you vanquish him several times, realizing that you are stronger than he is and he cannot win. But the yetzer hara will never leave you, whether you have defeated him once or even a hundred times… He will continue to ambush you throughout your lives.”
Why Did Elazar Speak?
The commentaries discuss why this section of the Torah was taught by Elazar, the Kohen, instead of Moshe:
- Anger Leads to Forgetting
Rashi (based on Pesachim 66b) says that since Moshe Rabeinu got angry at the soldiers (as explained above), he (momentarily) forgot this halacha. Based on this, Reish Lakish taught “Whoever gets angry his wisdom departs.”
- Taught in Front of his Teacher
According to the Chizkuni, Elazar was punished for teaching a halacha in front of his teacher (Moshe Rabeinu). In last week’s parsha G-d told Moshe that Yehoshua would need to consult with Elazar, the Kohen. As it says (Numbers 27:21) “He shall present himself to Elazar, the priest, who shall on his behalf seek the decision of the Urim before G-d.” Despite this we do not find that Yehoshua ever had the need to consult him. This was a punishment for speaking in front of Moshe. (I.e., even if Moshe forgot to teach this halacha, Elazar should have asked permission before speaking up.)
Fire and Water
In describing how to cleanse non-kosher utensils from their absorbed non-kosher flavors, Elazar said,
כָּל דָּבָר אֲשֶׁר יָבֹא בָאֵשׁ תַּעֲבִירוּ בָאֵשׁ וְטָהֵר אַךְ בְּמֵי נִדָּה יִתְחַטָּא וְכֹל אֲשֶׁר לֹא יָבֹא בּאֵשׁ תַּעֲבִירוּ בַמָּיִם
Any article that was used with fire—these you shall pass through fire and they shall be clean, except that they must be cleansed with the mikvah waters; and anything that was not used with fire, you must pass through water .
Rabbi Yosef Chayim of Baghdad (known as the Ben Ish Chai) writes (in Aderet Eliyahu) that this verse is alluding to the proper way to do Teshuvah. Since the sins one transgresses make a person impure, doing Teshuvah is similar to the kashering process in that they both cleanse impurities. The Talmud says (Megillah 31b) that if one is obligated to bring a sacrifice but cannot, he should study the section in the Torah about that sacrifice, and it will be considered as though he had offered it. As such, this verse is alluding to doing Teshuvah for both types of sins, those which would need a sacrifice and those which would not (for example, lying, flattery and lashon hara).
In this vein, he interprets the above verse as follows:
“Any article that was used with fire” refers to sins for which a sacrifice (burnt in fire) is appropriate.
The way to cleanse such sins is to “pass through fire” i.e., study the sections of Torah about sacrifices. (Torah is called fire, see Jeremiah 23:29.) However, this is not sufficient to cleanse one of the effects of the sin. One must also show sincere regret by crying bitter tears and begging G-d for forgiveness. This is why the verse continues and says, “They must be cleansed with the mikvah waters” i.e., one must also cleanse one’s sins through the purifying waters of one’s tears.
As far as sins for which no sacrifice is necessary, one achieves atonement simply by sincerely regretting the sin, resolving not to repeat it, and crying to G-d, begging that He forgive him. This is alluded to in the end of the verse, “Anything that was not used with fire (a sin for which no sacrifice with fire was necessary) you must pass through water (i.e., cleanse it through tears).”
Doing Teshuvah on Shabbos
The verse continues and says,
וְכִבַּסְתֶּם בִּגְדֵיכֶם בַּיּוֹם הַשְׂבִיעִי וּטְהַרְתֶּם וְאַחַר תָּבֹאוּ אֶל הַמַּחֲנֶה
“On the seventh day you shall wash your clothes and be clean, and after that you may enter the camp.”
Continuing on the theme of Teshuvah the Ben Ish Chai explains that this verse is encouraging us to wash our spiritual garments (i.e., our behaviour) on the seventh day of the week, Shabbat. We can do this by using our extra time on Shabbat to:
- Study Torah
- Examine our deeds
- Attend classes where we learn how to better ourselves and are inspired to do so.
Do Teshuvah in Your Seventh Decade
In addition, the Ben Ish Chai says that the command to wash one’s garments on the seventh day alludes to the fact that one should wash one’s spiritual garments (as above) in the seventh decade of their life so that they are spiritually pure whenever they are called to the Next World.
Since the Torah portion discusses kashering, the rest of this article will discuss how to kasher knives.
Here are the various methods for kashering knives, when they are necessary and what they work for.
- Boiling Water
If one has a knife that has absorbed a non-kosher flavor through heat (e.g., it was used to cut a hot non-kosher food), it must be kashered by immersion in boiling water (see Yoreh De’ah 121:7). Before doing this, one must clean the knife to make sure there is no food residue on it. This is especially important in the area where the blade connects with the handle.
- Sharpening the Knife
Although the opinion of the Shulchan Aruch is that sharpening the knife is a valid way to kasher it (see ibid), in practice one cannot use this method to kasher knives because the Shulchan Aruch is talking about one who removes a layer of metal from the entire blade of the knife, and this is not the way we sharpen knives today.
- Plunging It into the Ground 10 Times
If one has a kosher knife that was used to cut cold non-kosher foods many times, one can kasher it by plunging it in the ground ten times (ibid based on Avodah Zarah 76b). The same applies to a knife that was used to cut something non-kosher and was left dirty for some time (Hilchot Bassar BeChalav by Rabbi Dovid Hofshtater, page 430). One must use hard earth and one must do each plunge in a different spot as each plunge softens the earth in that spot. The same method works for kashering a dairy knife that was used to cut cold meat several times or a meat knife that was used to cut cheese several times.
The Pri Chadash (10:7) explains that this method of kashering is necessary for knives as they are used with pressure and the grime they accumulate is difficult to clean with standard cleaning methods.
- Washing Well
A knife used once mistakenly for a cold non-kosher food (or dairy instead of meat or vice versa) can be kashered by simply washing it well with water (Hilchot Bassar BeChalav, pg. 435).
Using with Cold Foods on a Temporary Basis
If one has a knife that absorbed a non kosher flavor through heat, one can use the “plunging in earth” method to kasher it for temporary use with cold foods. One should not use it on a permanent basis however, without kashering it with boiling water as this can lead to mistakenly using it with hot food.
Using with Sharp Foods
Some say that such a knife may even be used to cut sharp foods (on a temporary basis). Others say that for use with sharp foods one must kasher it fully in boiling water.
This argument is based on the following story (in Avodah Zarah ibid):
King Shapur, Mar Yehudah and Bati bar Tuvi
Mar Yehuda (an important personage of the house of the Exilarch) and Bati bar Tuvi (a wealthy man) were once sitting before King Shapur of Persia. The king’s servants brought an etrog before them. The king cut a slice and ate it, and then he cut a slice and gave it to Bati bar Tuvi. He then stuck the knife ten times in the ground, cut a slice and gave it to Mar Yehuda. (Evidently this king was well versed in Jewish law.) Bati bar Tuvi said to him: “And is that man [referring to himself] not Jewish?” King Shapur said to him: “I am certain of that master (Mar Yehuda), that he is meticulous about halacha; but I am not certain of that master (referring to Bati bar Tuvi), that he is meticulous in this regard.”
There are some opinions who hold that King Shapur said to Bati bar Tuvi: “Remember what you did last night.” (The Persian practice was to present a woman to each guest. Mar Yehuda did not accept the woman who was sent to him, but Bati bar Tuvi did, and therefore he was not assumed to be meticulous with regard to eating kosher food.)
Is an Etrog Sharp?
Since an etrog is sharp, the Rashba (Torat HaBayit, 2:4) infers from this story that plunging a non-kosher knife in the ground is effective even for cutting sharp foods. This the ruling of the Shulchan Aruch (Y.D. ibid).
The Chelkat Binyamin (121:7 based on the Pri Megadim) explains that, according to the Rashba, plunging the knife in the ground cleans the surface of the knife, extracts flavors from the surface of the knife, and weakens the flavors absorbed in the entire knife. Thus, even cutting something sharp (which usually extracts the flavor from the entire knife as is evident from Y.D. 96) is permissible.
Others say that an etrog is not as sharp as a radish and other sharp foods (Bechor Shor, based on Tosfot, quoted in Pit’chai Teshuvah 9, on Y.D. ibid). They therefore rule that one may not cut sharp foods with a knife that had been plunged into the ground until it is kashered with boiling water. In practice the halacha is not clear (Chelkat Binyamin on Y.D. ibid).
Using Steel Wool
Some say that nowadays one can clean knives with steel wool or other abrasive methods and that this is just as good as plunging it in the ground. Others say that we should continue to kasher knives by the traditional method mentioned in the Talmud.
Some say that nowadays, it is best to clean a knife well with steel wool or the like and then pour hot water on it. (This applies to knives that did not absorb with heat as explained above as such knives should be kashered in boiling water.) [See sources quoted in Hilchot Bassar BeChalav, pg. 435.]
May we Merit to do a True Teshuvah!
Wishing you a Shabbat Shalom Umevorach and a Chodesh Tov!