'Forever' in the Bible

As for the assembly, there shall be one [and the same] statute for you [of the congregation] and for the stranger who is a resident alien with you, a permanent statute throughout your generations; as you are, so shall the stranger be before the Lord.

as a reminder to the sons of Israel so that no layman—that is, one who is not of the descendants of Aaron should approach to offer incense before the Lord; so that he will not become like Korah and as his company—just as the Lord had said to him through Moses.

Then the Lord spoke to Aaron, “Now behold, I [the Lord] have entrusted you with My heave offerings, even all the holy gifts of the Israelites, I have given them to you as a portion, and to your sons as a continual allotment.

This also is yours: the heave offering of their gift, including all the wave offerings of the Israelites. I have given them to you and to your sons and to your daughters with you as a continual allotment; everyone in your household who is [ceremonially] clean may eat it.

All the offerings of the holy things, which the Israelites offer to the Lord I have given to you and to your sons and your daughters with you as a continual allotment. It is an everlasting covenant of salt [that cannot be dissolved or violated] before the Lord to you and to your descendants with you.”

Only the Levites shall perform the service of the Tent of Meeting (tabernacle), and they shall bear their iniquity; it shall be a statute forever throughout your generations, that the Levites shall have no inheritance [of land] among the children of Israel.