The Theory of Conservation of Holiness
Bamidbar (Numbers 1:1-4:20 )
As the Book of Bamidbar begins, the Israelites have been encamped at the foot of Sinai for over a year, and we begin to sense a stirring that will soon become forward movement: First, instructions are given for conducting a census, followed by demarcation of marching formations and tribal flags. The mass of people who took leave of Egypt is organized according to tribal affiliation, and the tribes are grouped into mahanot (camps) as they begin preparations for the second part of their march, from Sinai to the Promised Land.
One tribe, however, is not included in any of these preparatory steps: the Levites are neither counted in the census nor included in the marching formation. The Levites, unique among the tribes, have no flag or standard around which they gather. They are a tribe with a singular mandate, designated to serve in the Mishkan; they belong to God.
This had not always been the case; until a certain point in time, the tribe of Levi had been like any of the other tribes, equal in every way to the other eleven. Moreover, the unique designation of dedicated service to God had not previously been the purview of any one tribe. Originally, the firstborn of each and every Israelite family was dedicated to Divine service. What happened? Why were the firstborn displaced and replaced by the Levites? The Torah does not provide a clear answer:
God spoke to Moshe, saying: I have separated the Levites from the children of Israel, so that they may take the place of all the firstborn among the Israelites, and the Levites shall be Mine. This is because every firstborn became Mine on the day I killed all the firstborn in Egypt. I then sanctified to Myself every firstborn in Israel, man and beast alike, [and] they shall remain Mine. I am God. (Bamidbar 3:11-13)
This passage explains how and why the firstborn were initially sanctified with a special holiness: On the night all the firstborn were killed in Egypt, the firstborn of the Israelites were spared. Apparently, this was neither arbitrary nor without repercussions: The Israelite firstborn were saved for a purpose, to serve God in the Temple, and because they were saved they were granted a higher status of holiness. Why was this holiness forfeited? When were the firstborn replaced by the Levites?
On two different occasions, the firstborn sons were given the opportunity to carry out their unique role. These two occasions were very different from one another, both in circumstance and in their implications and ramifications: The first opportunity that arose was at the foot of Mount Sinai, as the people prepared for the Revelation. Offerings were brought,(1) and it is presumed that the firstborn served as religious functionaries for the exalted religious experience that prepared the people for what was to follow. The next "opportunity" presented itself some forty days later, when Moshe was nowhere to be seen and the situation began to spiral out of control: A golden calf was formed and the people brought offerings and worshiped the icon they had created.(2) Once again, the firstborn acted as "kohanim," preparing and offering the sacrilegious sacrifices and leading the way for the nation as a whole. In so doing, the firstborn forfeited their place as "kohanim," and were replaced by the "first responders," the Levites who answered Moshe's call to arms and quashed the rebellion.
Interestingly, the holiness that had belonged to the firstborn did not simply dissipate when they forfeited their unique role. There is, it seems, a "theory of conservation of holiness": Holiness is neither created nor destroyed by human behavior. The source of holiness is God, and when the subject upon which holiness is bestowed becomes unable or unworthy to maintain the required level of proximity to God, the holiness is transferred to a different subject. Thus, after the firstborn strayed, the Levites, who stood passionately in defense of God and real holiness and eschewed the golden imposter, were endowed with the holiness wrested from the firstborn in an act of transference.
On the other hand, despite the shift of their special role to the Levites, the firstborn retained a vestige of their previous holiness; despite the relative spiritual estrangement, holiness does not disappear. From that point, both the firstborn and the Levites are endowed with holiness, even though only the Levites can serve in the Temple. The holiness of the firstborn, the spiritual glow of serving God at Sinai, is never erased, even though Temple service is no longer an option. From that time forth, the firstborn of all non-Levites must be redeemed, released from the obligation of service for which they are no longer worthy.
Such is holiness: it does not disappear. Tasks and responsibilities may be reassigned to others, but the holiness of the firstborn is retained. Perhaps this idea holds out hope for the entire Jewish People: The moment they worshipped the golden calf, in violation of the covenant they had made with God only days earlier, God could have turned His back on them entirely, for they had proven themselves unworthy of the holy destiny to which God had appointed them. And yet, we continue to be God's Chosen People, "a kingdom of priests and a holy nation." The holiness with which we were imbued at Mount Sinai is everlasting. Its source is God Himself, and therefore it, too, is eternal.
For an in-depth analysis see: http://arikahn.blogspot.co.il/2014/05/audio-and-essays-parashat-bmidbar.html
1. Shmot 24:5.
2. Shmot 32:6.