The penultimate pasuk of our parasha, Yitro, focuses on the law of constructing an altar made of stone: “And when you make for Me an altar of stones, you shall not build them of hewn stones, lest you wield your sword upon it and desecrate it.” (Shemot 20:22). The Rambam codifies this commandment:
“The 79th prohibition is that we are forbidden from constructing an altar from stones that have come in contact with metal. The source of this mitzvah is G-d’s statement, exalted be He: ‘[When you build a stone altar for Me,] do not build it out of cut stone. Because your sword was lifted against it, [you have profaned it].’ If one builds an altar from such stones it is invalid and offerings may not be brought on it.” (Sefer HaMitzvot)
The Mechilta d’Rabbi Yishmael is the halachic midrash to Shemot. Rashi bases himself on this work’s explanation of our verse in his interpretation as to why metal-hewn stones result in a desecration of the stone altar: “The altar makes peace between Israel and their Father in heaven. Therefore, the cutter and destroyer shall not come upon it. The matter is a kal vachomer [a fortiori] conclusion — for if [concerning the] stones, which neither see, hear, nor speak, because [of the fact that] they make peace, the Torah said, ‘You shall not wield iron upon them’ (Devarim 27:5), how much more so [are we certain that] one who makes peace between husband and wife, between family and family, between man and his fellow, will have no troubles befall him!”
Additionally, in the original version of the mechilta, Rabban Yochanan ben Zakkai brings the verse, “You shall build the altar of the L-rd, your G-d, out of whole stones (avanim shleimot tivneh) (Devarim 27:6). He notes the etymological similarity between “shleimot” and “shalom,” and states, “[These] are stones that bring about peace.” (Mechilta d’Rabbi Yishmael, Mesechta d’b’Chodesh, parasha 11) Therefore, based on the mechilta and Rashi’s formulation of same, it is clear that the underlying rationale of the prohibition of “constructing an altar from stones that have come in contact with metal” is the pursuit of shalom between man and G-d (through the offerings brought thereupon) and, metaphorically, between man and his fellow man.
The Rambam helps us further define the holistic import of shalom, and its pursuit through a seminal halachic and philosophical statement that appears as the final words of Sefer Zemanim. Therein, he discusses a situation of financial triage in which one has extremely limited funds. He presents two scenarios: One has money to purchase either Shabbat or Chanukah candles, and one has money to buy Shabbat candles or wine for kiddush. What takes precedence?
Maimonides is unequivocal in his response: “Ner beito kodem meshum shalom beito” (“Shabbat lights must be purchased prior [to either Chanukah candles or wine] because of the peace of his home”). We must remember that the Shabbat lights in this historical context may very well have been the only lights in the home. Therefore, without this small amount of illumination, family members would trip over one another, arguments would ensue, and the Shabbat evening would become a dark and fractious time. As a result, and in an effort to buttress shalom bayit, Maimonides codifies the law that Shabbat candles take precedence over fulfilling either the mitzvah of kiddush or Chanukah candles. Clearly, the value of shalom bayit outweighs these other mitzvot. His concluding words, though few in number, are a virtual paean to shalom:
“Behold, [one must remember] that the Divine Name itself was erased [in the Sotah process] in an effort to bring about peace between a man and his wife. Great is the ultimate peace, for the entire Torah was given to bring about peace in the world. As it states (Sefer Mishle 3:17): “Its ways are ways of pleasantness, and all its paths are peace.” (Hilchot Megillah and Chanukah, 4:14)
“[May] He Who makes peace in His heights, may He in His compassion make peace upon us and upon all Israel” (The Complete Artscroll Siddur). May this blessing of peace be placed upon all mankind, soon, and in our days. V’chane yihi ratzon.