From thirty years old and upward to fifty years old you shall number them, all that enter in to perform the service, to do the work in the tabernacle of the congregation.
This is that which pertains to the Levites. From twenty-five years old and upward they shall go in to wait upon the service of the tabernacle of the congregation.
But they shall minister with their brothers in the tabernacle of the congregation, to keep the charge; only he shall not serve at a service. So you shall do to the Levites as to their duties.