Numbers 7:9

But unto the sons of Kohath he gave none, for the service of the sanctuary was upon them: they bore what they carried upon the shoulder.

Numbers 3:31

And their charge was the ark, and the table, and the candlestick, and the altars, and the utensils of the sanctuary with which they ministered, and the curtain, and all that belongs to its service.

2 Samuel 6:13

And it was so, that when they that bore the ark of Jehovah had gone six paces, he sacrificed an ox and a fatted beast.

Numbers 4:4-16

This shall be the service of the sons of Kohath in the tent of meeting: it is most holy.

2 Samuel 6:6

And when they came to Nachon's threshing-floor, Uzzah reached after the ark of God, and took hold of it; for the oxen had stumbled.

1 Chronicles 15:3

And David assembled all Israel to Jerusalem, to bring up the ark of Jehovah to its place that he had prepared for it.

1 Chronicles 15:13

For because ye did it not at the first, Jehovah our God made a breach upon us, for that we sought him not after the due order.

1 Chronicles 23:26

and the Levites also have no more to carry the tabernacle, nor any of its vessels for its service.

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 candlestick, and the altars, and the utensils of the sanctuary with which they ministered, and the curtain, and all that belongs to its service.
Numbers 4:4
This shall be the service of the sons of Kohath in the tent of meeting: it is most holy.
2 Samuel 6:6
And when they came to Nachon's threshing-floor, Uzzah reached after the ark of God, and took hold of it; for the oxen had stumbled.
1 Chronicles 15:3
And David assembled all Israel to Jerusalem, to bring up the ark of Jehovah to its place that he had prepared for it.
1 Chronicles 23:26
and the Levites also have no more to carry the tabernacle, nor any of its vessels for its service.