At first glance, the purpose of the Tabernacle and the wonder of the High Priest and his magnificent dress would seem to be to inspire people. It is certainly true that human beings are affected by things that are aesthetically pleasing. We create a positive association for that which looks good and sounds beautiful. Good-looking people are deemed more trustworthy and likable, even though there is no objective reason for it.
And so it is important for our Jewish communal institutions to create that good impression. And, yet, the purpose of the garments of the High Priest go way beyond simply making a good impression.
The centerpiece of his eight garment uniform was the Breastplate. In it, were 12 stones representing the 12 tribes of Israel. They were known as the "Urim Vetumim." This means that they "lit up and perfected." Indeed, these stones had a supernatural power to them. In the times of the first Temple, the King, when faced with major decisions of state, could consult the Urim Vetumin to gain Divine guidance. All of the letters of the Hebrew alphabet were on those stones, and upon being asked, the letters indicating the correct answer would light up miraculously.
This event would only happen when the High Priest wore the Breastplate. Only the combination of this holy individual with the holy adornment could bring that direct Divine communication.
Not every High Priest was worthy of it. Throughout the entire period of the Second Temple, the stones either were not present or did not function. The Talmud has uncomplimentary things to say about many of the High Priest in that period of time. Some of them were elitist, some refused to accept the principles of the Oral Law. The spiritual level of the High Priest seems to be critical to the functioning of the Urim Vetumin.
The commentaries all ask how it was possible for a High Priest in Second Temple times to fulfill his duties if there were no Urim Vetumim. The rule is that a High Priest who officiates without all of the required garments is liable to death at the hands of heaven! A couple of answers are offered. One is that the Breastplate was, indeed, there, just that the stones were not. Others disagree, and claim that the breastplate without the stones is as if it's nonexistent. Rather, they claim that the stones were there as well, but they no longer had the magical function.
This law of "mechusar begadim," or lacking required garments is explained by the commentaries in a striking way. The man who has been the High Priest but attempts to perform the Temple service without the garments is not, at that time, the High Priest. It is as if he is not even a Cohen, simply a regular individual who inserted themselves into the Temple ritual. About such a person the Torah says, "and the stranger that comes close (to perform the Service) shall die."
In other words, the clothing makes the man, or, in this case, the High Priest.
The Sefer Hachinuch, a later medieval scholar, provides a novel understanding of the role of these garments. Every single garment the High Priest wore had to cover his entire person. There was to be no significant flesh showing. In this way, the High Priest would see the symbols of holiness upon his entire person. In other words, the garments were not to impress and inspire the people coming into the Tabernacle, but rather to reminds the High Priest himself of his unlimited potential for holiness.
This is an inspiring concept. A human being who is in full perception of the innate holiness within himself is capable of becoming a conduit for direct communication from God. He wears upon his person, numerous times, the Divine Name. Such is the potential of the human being, created in the image of God.
What is even more inspiring is the fact that the first High Priest was Aaron. Why so? Because Aaron was a very human being. He had imperfections in his past, specifically the fact that he somehow facilitated the episode of the Golden Calf. Instead of being a disqualifier, perhaps that is the true reason he was the perfect person to be the first dedicated High Priest.
What is the role of the High Priest, anyway? To bring atonement and forgiveness to the people. There is no such thing as a completely perfect individual, but if there were, he would not be appropriate for this exalted position. He could not relate to the rest of the people who come to the Temple seeking redemption and cleansing. Nobody would feel any affinity for him, and thus his influence would not be effective.
Thus, we can resolve our doubt about the role of the Tabernacle and the splendiferous garments of the High Priest. They are not for the glory of God, but to show all of us the glory of God that resides in our own souls. The synagogue is not a cathedral where the faithful are made to feel very small, but rather it is a Tabernacle where the faithful reminded of just how great and holy they are.
The Temple and the synagogue are not places we go to discharge duties to God and then go home to our lives. They are places we go to stock up on spiritual self-esteem in order to bring that holiness with us out into the world and back into our homes. When we see a man, flawed as we are, who covers himself in holiness and reaches the level where God speaks through the Breastplate upon his person, we see what we are capable of achieving. And when the man treats us with love and honor, we are motivated to achieve that holiness.
