G‑d commands the Jewish people: "An eternal flame should always be kept burning on the altar; it should never be extinguished."

The fire on the altar where the sacrifices were offered should always continue to burn. In the Holy Temple, there was a special chamber where hot coals were kept burning, so that the fire on the Alter could be relit whenever necessary.

When G‑d commanded the Jewish people to build the Tabernacle, He said: "And I will dwell within them." Shouldn't the verse have said "I will dwell within it"? It says "them" to teach us that every Jewish person is like a miniature Temple. Every Jew must always have a fiery love for G‑d in his heart, just like the fire which burns all the time on the altar.

In the Talmud, our Rabbis teach us more details about this mitzvah: The fire on the altar was to be kept burning even on Shabbat and even when we are impure.

In the same way, we Jews should always feel a deep love for G‑d, whether we are on a level of Shabbat or on a level of impurity.

What do we mean by "a level of Shabbat"?

On Shabbat, we wish each other Shabbat Shalom. The Hebrew word Shalom comes from the root of the Hebrew word whole and complete (shaleim). We feel complete on Shabbat. We relax and we do not worry about our weekday work, acting as if it were completed.

On Shabbat, we are also given an extra Shabbat soul that helps us pray better, learn better, and understand G‑d's holiness better. But a Jew on the level of Shabbat might only pay attention to his learning and understanding, and he might ignore his feelings. So G‑d reminds him of the "eternal flame... even on Shabbat." The burning love for G‑d in our hearts should never relax.

Then our Rabbis add, "even when impure." Even if a Jew is impure, he should dig deep into his heart and bring out the love for G‑d which is always there.