Both the cleansing and the consecration of God's servants, the priests, take place through sacrifice. This is understandable: sacrifice was always the main form of communion with God, both in Yahwism and in paganism...
Both the cleansing and the consecration of God's servants, the priests, take place through sacrifice. This is understandable: sacrifice was always the main form of communion with God, both in Yahwism and in paganism. A shared, common meal of a human being with God or with the gods: such is the original meaning of sacrifice.
What a pagan needed above all from an encounter with his gods or spirits was power; what a Yahwist needed from his God was holiness. Participation in the world of God's presence. In the Kingdom, insofar as it was then accessible and open to the world. This participation is called "consecration" in the Bible, and "sacred" means having become part of the sacred space where God's presence dwells. Only it can both cleanse and consecrate a person.
It would seem strange: in that case, a person is prepared for service in the same way in which he will later have to carry out that service, since the priest will precisely have to offer sacrifices that cleanse and consecrate others. If, however, we think about the essence of worship and communion with God, we will see nothing strange here. Who, indeed, could prepare a person for service to God except God Himself?
This is not a matter of some special knowledge or skills, or even of some special spiritual or ascetic practices. What is needed here is experience of the kind that in antiquity was called initiation: the experience of direct contact with the reality with which one will later have to deal and interact constantly.
The future priest needs to sense and experience this reality personally, and then become aware of it, aware of it as something that completely changes his life, making him a different person. Something like what Abraham and Jacob once realized during their meetings with God. Of course, no rituals by themselves can guarantee anything here.
Even God's presence by itself cannot be a guarantee here. Everything depends first of all on the one being consecrated, on how open he is to God and how ready he is for change. If he is ready, he has every possibility of becoming a truly new person and God's servant; if not, he will remain merely someone in costume, despite all the rituals and even despite the fact that God really was there where those rituals were performed. The choice belongs to the person.