Let’s take a look at the source for this mitzvah.
Subsequent to the Jews winning the war against the Midianite nation and receiving the spoils of war, including their cooking utensils, the Torah states the following, “Elazar the Kohen said to the men of the legion who came to the battle; ‘This is the decree of the Torah… the gold and the silver, the copper, the iron, the tin and the lead, everything that comes [by way of cooking] into the [open] fire you shall pass through the fire and it will be purified, however it must be purified in the waters ‘of a nidah’, and everything that would not come into the fire you shall pass through the water.’”
The Torah is teaching us two important requirements when receiving vessels from gentiles. Firstly, the mitzvah of “hagalas keilim,” or the koshering of the vessels. This involves burning out any non-kosher absorption in the walls of the vessel by returning to fire any vessel used with fire, such as a spit holding the meat over an open fire or the racks of a barbeque. Any vessel used to cook with liquid, such as a pot or the stirring utensils used in the pot must be submerged in boiling water to purge out any absorption, thereby rendering the vessel pure of non-kosher tastes and it becomes kosher as the verse says at the end of that section. The Torah adds, however, one more step, “…however, it must be purified in the ‘water of a nidah.” What water is this referring to?
The classical commentary Rashi to that verse explains that the vessels, after purged of non-kosher absorption, must subsequently be purified in a similar body of water as that which a woman elevates herself monthly, namely, the waters of a Mikveh. This mitzvah is referred to as “tevilas keilim,” the submersion of vessels. This obligation applies even to vessels that have never been used with non-kosher food and even if they are new. As long as they are transferred from the possession of a gentile to a Jew, whether by purchase, as a gift (or the spoils of war!), before a Jew uses that utensil for food preparation or serving, it must first be immersed in a Mikveh.
The commentaries explain that the foundation of this mitzvah goes to the core of Jewish living. We consider the act of eating to be a very holy endeavor, not the mundane outlook on food that exists in the world at large. This is part of the reason we don’t ingest a morsel of food without first reciting a blessing, making sure it is kosher, and to have the proper state of mind; in order to ensure that we are not simply engaging in the animalistic act of consuming calories, but connecting to G-d through the food which He has endowed us. In order to elevate the utensils utilized in the preparation and consumption of food to a level which makes them fit for this connection to something higher, they are first immersed in a mikveh. A mikveh is a unique body of water specially crafted with the innate ability to elevate the mundane to the sublime.
On the level of Torah obligation, one need only immerse metal utensils in a Mikveh; the Torah only requires those for reasons beyond the scope of this column. Rabbinical law, however, requires we treat glass like metal and it, too, requires submersion in a mikveh prior to its use. This, however, applies to utensils used for food preparation only. There is no need for you to submerge the candlesticks.
Rabbi Yerachmiel Fried