At the conclusion of the portion Tetzaveh1 the Torah commands that an altar be built and placed within the Tabernacle for the sole purpose of offering incense. This Interior Altar supplemented the Exterior Altar (placed in the courtyard of the Mishkan), upon which all other offerings, libations, etc., were brought.

Why were two altars necessary, one in the courtyard and limited to offerings, the other within the Mishkan itself and limited to incense; why would one altar not suffice?

Chassidus explains2 that the two altars corresponded to two levels of Divine revelation: the Interior Altar to the internal revelation that transcends creation, the Exterior Altar to the more overt and less revelatory level of G‑dliness that descends within creation.

The External Altar — corresponding as it did to the more external level of G‑dliness — was thus in a less sacred section of the Mishkan , while the Interior Altar — corresponding as it did to the more internal level of G‑dliness — was found within the more sacred portion.

In terms of man’s spiritual service, we find two general categories as well: a) that of refining and separating good from evil and elevating the good to holiness — a form of service known as birurim ; b) a higher level, where one does not have to combat evil, rather one strives to achieve a greater degree of unity with G‑d.

The Exterior Altar, corresponding as it did to the G‑dliness found within creation — with creation containing aspects of both good and evil — was limited to the less superior form of service, that of elevating the physical through sacrificial offerings: the service of birurim.

The Interior Altar, on the other hand — corresponding to G‑dliness as it transcends evil — was for the spiritually superior service of incense, or ketores , etymologically related to kotar , or cleaving3 — achieving a greater degree of cleaving to G‑d.

Parallels to the two altars are also to be found within all Jews, for the Mishkan as a whole is found within the heart of every Jew, as our Rabbis comment4 on the verse,5 “They shall make for Me a Sanctuary and I will dwell in them” — “It does not say ‘I will dwell in it’ rather, ‘I will dwell in them’ — in the ‘heart’ of each and every Jew.”

Here, too, the Interior and Exterior Altar correspond to the internal and external levels of the Jewish heart:6 the external level of a Jew’s service — the external level of his heart — is occupied in the service of birurim , while the internal level is occupied in achieving a greater degree of cleaving to G‑d.

Simply stated, a Jew is supposed to occupy himself not only in the study of Torah and the performance of mitzvos , but also in permissible things such as eating, drinking and the like. However, this is not to say that such mundane matters are indulged in for their own sake; the intent should be to use the activity for a sacred purpose7 — “All one’s actions should be for the sake of Heaven.”8

A person may mistakenly be led to think that since his involvement with the physical is entirely for a spiritual purpose, he may therefore involve not only the heart’s external level, but its internal level as well.

But since these are, after all, physical actions, one should employ only the external aspect of the heart in performing them; the internal and more profound level — one’s Interior Altar — should be reserved for matters of a purely holy nature.

However, in order to achieve this superior form of service, a person must first employ his Exterior Altar in the service of birurim , imbuing all his physical thoughts, words and deeds with sacred purpose. Only then can he utilize his Interior Altar to achieve a greater degree of cleaving to G‑d.

Based on Likkutei Sichos , Vol. VI, pp. 185-187.