Numbers 8:15

Then after that the Levites may go in to serve the tent of meeting. But you shall cleanse them and present them as a wave offering;

Numbers 8:11

Aaron then shall present the Levites before the Lord as a wave offering from the sons of Israel, that they may qualify to perform the service of the Lord.

Numbers 8:13

You shall have the Levites stand before Aaron and before his sons so as to present them as a wave offering to the Lord.

Exodus 29:24

and you shall put all these in the hands of Aaron and in the hands of his sons, and shall wave them as a wave offering before the Lord.

Numbers 3:12

“Now, behold, I have taken the Levites from among the sons of Israel instead of every firstborn, the first issue of the womb among the sons of Israel. So the Levites shall be Mine.

Numbers 3:23-37

The families of the Gershonites were to camp behind the tabernacle westward,

Numbers 4:3-32

from thirty years and upward, even to fifty years old, all who enter the service to do the work in the tent of meeting.

1 Chronicles 23:1-32

Now when David reached old age, he made his son Solomon king over Israel.

1 Chronicles 25:1-26

Moreover, David and the commanders of the army set apart for the service some of the sons of Asaph and of Heman and of Jeduthun, who were to prophesy with lyres, harps and cymbals; and the number of those who performed their service was:

Treasury of Scripture Knowledge

Summary

And after that shall the Levites go in to do the service of the tabernacle of the congregation: and thou shalt cleanse them, and offer them for an offering.

Bible References

Go in

Numbers 8:11
Aaron then shall present the Levites before the Lord as a wave offering from the sons of Israel, that they may qualify to perform the service of the Lord.
Numbers 3:23
The families of the Gershonites were to camp behind the tabernacle westward,
Numbers 4:3
from thirty years and upward, even to fifty years old, all who enter the service to do the work in the tent of meeting.

And offer

Numbers 8:11
Aaron then shall present the Levites before the Lord as a wave offering from the sons of Israel, that they may qualify to perform the service of the Lord.
Numbers 3:12
“Now, behold, I have taken the Levites from among the sons of Israel instead of every firstborn, the first issue of the womb among the sons of Israel. So the Levites shall be Mine.