Throughout the Torah, there are many places where it seems as if the Torah could have written a different word or phrase to transmit the same message, but instead chooses a specific word or phrase. Behind every word and letter there is great meaning. For instance, the word, “VaYakheil” (Shemot 35:1), and the Pasuk, “Lo Tevaaru Eish BeChol Moshevoteichem BeYom HaShabbat,” “Do not light a fire in any of your dwelling places on Shabbat” (35:3) could have been replaced with other words or phrases that would get the same message across. Why does the Torah use these words and phrases?
Sheim MiShemuel comments that the word “VaYakheil” (from the root Kahal, a congregation) is used because before the Cheit HaEigel, even one person could build the Mishkan. Now, after the sin, the Mishkan could only be built by tapping the collective strength of all of Klal Yisrael, an entire Kehillah. The Admor of Tsharaktov suggests that the Torah refers to Kehillah in the sense that all of Bnei Yisrael can perform the Mitzvot, no matter how different each person may be from his fellow. HaDerash VeHaIyun remarks that VaYakheil implies that we constitute a nation, a Kehillah, and have peace amongst ourselves only if we engage in proper behavior. Without such behavior, we cease to be a true nation, as happened to Bnei Yisrael during the Cheit HaEigel. Rashi interprets the use of VaYakheil along with a later mention of Yom Kippur to teach that a person must always seek to appease his friend, not only during the Aseret Yemei Teshuva.
One might also ask why kindling a fire had to be explicitly mentioned as a Melachah. The Shelah observes that “Eish” here may not really mean fire, but rather the heat of an argument. If so, then the Pasuk is teaching that one should make a special effort to avoid disputes on Shabbat. The Alshich gives an alternate explanation for how fire affects our conduct on Shabbat. He cites a Midrash that states that whenever someone sins on Shabbat, he relights the fires of Gehinnom. Therefore, one should be extremely careful to comport himself on Shabbat. Tiferet Yonatan offers a different explanation. He states that fire is singled out because one might have thought that only Melachot that were created in the first six days of creation are included in the prohibition of Melachah on Shabbat (since Shabbat is supposed to remind us of creation, as we say in Kiddush “Zikaron LeMaaseih Bereishit”). Chazal teach that fire was not created until the first Motzaei Shabbat, so one might have thought creating fire is permitted on Shabbat. To forestall this misapprehension, the Torah singled out kindling fire as a Melachah.
These are but a few examples of how every word in the Torah has profound meaning. We should all merit understanding the great depths of each word of the Torah.