New Revised Standard Version
They may assist their brothers in the tent of meeting in carrying out their duties, but they shall perform no service. Thus you shall do with the Levites in assigning their duties.

Contemporary English Version
They may help the other Levites in their duties, but they must no longer be responsible for any work themselves. Remember this when you assign their duties."

New American Bible
They shall assist their fellow Levites in the tent of meeting in performing their duties, but they shall not do the work. This, then, is how you are to regulate the duties of the Levites.

Douay-Rheims Bible
And they shall be the ministers of their brethren in the tabernacle of the covenant, to keep the things that are committed to their care, but not to do the works. Thus shalt thou order the Levites touching their charge.

And they shall be the ministers of their brethren in the tabernacle of the covenant, to keep the things that are committed to their care, but not to do the works. Thus shalt thou order the Levites touching their charge.

to keep

Numbers 1:53 But the Levites shall pitch their tents round about the tabernacle, lest there come indignation upon the multitude of the children of Israel, and they shall keep watch, and guard the tabernacle of the testimony.

Numbers 3:32 And the prince of the princes of the Levites, Eleazar, the son of Aaron the priest, shall be over them that watch for the guard of the sanctuary.

Numbers 18:4 But let them be with thee, and watch in the charge of the tabernacle, and in all the ceremonies thereof. A stranger shall not join himself with you.

Numbers 31:30 Out of the moiety also of the children of Israel thou shalt take the fiftieth head of persons, and of oxen, and asses, and sheep, and of all beasts, and thou shalt give them to the Levites that watch in the charge of the tabernacle of the Lord.

1 Chronicles 23:32 And let them keep the observances of the tabernacle of the covenant, and the ceremonies of the sanctuary, and the charge of the sons of Aaron their brethren, that they may minister in the house of the Lord.

1 Chronicles 26:20-29 Now Achias was over the treasures of the house of God, and the holy vessels. . . .

Ezekiel 44:8,11 And you have not kept the ordinances of my sanctuary: but you have set keepers of my charge in my sanctuary for yourselves. . . .

and shall

1 Timothy 4:15 Meditate upon these things, be wholly in these things: that thy profiting may be manifest to all.