The Levites are to perform the work of the Tent of Meeting, and they must bear their iniquity. This is a permanent statute for the generations to come. The Levites will not receive an inheritance among the Israelites.
Jewish Publication Society of America Version (JPS1917) - Numbers 18:23 >But the Levites alone shall do the service of the tent of meeting, and they shall bear their iniquity; it shall be a statute for ever throughout your generations, and among the children of Israel they shall have no inheritance.