Numbers 7:9

but, unto the sons of Kohath, gave he none, - because as to the laborious work of the sanctuary which pertained unto them, upon their shoulders, were they to carry it.

Numbers 3:31

And their charge, was - the ark and the table and the lampstand and the altars, and the utensils of the sanctuary wherewith they were to minister, - and the screen, as to all the laborious work thereof.

2 Samuel 6:13

And so it was that, when they who bare the ark of Yahweh had stepped forward six paces, he sacrificed an ox and a heifer.

Numbers 4:4-16

This, shall be the labour of the sons of Kohath, in the tent of meeting, - the most holy things,

2 Samuel 6:6

And, when they came as far as the threshing-floor of Nachon, Uzzah thrust forth his hand unto the ark of God, and took hold of it, for the oxen were restive.

1 Chronicles 15:3

So David convoked all Israel, unto Jerusalem, - to bring up the ark of Yahweh, unto the place thereof, which he had prepared for it.

1 Chronicles 15:13

Because, at the first, ye, did not bring it , Yahweh our God brake forth against us, because we sought him not in the appointed way.

1 Chronicles 23:26

moreover also, as for the Levites, they have no need to bear the habitation, nor any of its vessels in the laborious work thereof.

Treasury of Scripture Knowledge

Summary

But unto the sons of Kohath he gave none: because the service of the sanctuary belonging unto them was that they should bear upon their shoulders.

Bible References

Because

Numbers 3:31
And their charge, was - the ark and the table and the lampstand and the altars, and the utensils of the sanctuary wherewith they were to minister, - and the screen, as to all the laborious work thereof.
Numbers 4:4
This, shall be the labour of the sons of Kohath, in the tent of meeting, - the most holy things,
2 Samuel 6:6
And, when they came as far as the threshing-floor of Nachon, Uzzah thrust forth his hand unto the ark of God, and took hold of it, for the oxen were restive.
1 Chronicles 15:3
So David convoked all Israel, unto Jerusalem, - to bring up the ark of Yahweh, unto the place thereof, which he had prepared for it.
1 Chronicles 23:26
moreover also, as for the Levites, they have no need to bear the habitation, nor any of its vessels in the laborious work thereof.