2 Chronicles 23:4

This is the thing that ye shall do: a third part of you, that come in on the sabbath, of the priests and of the Levites, shall be porters of the thresholds;

1 Chronicles 9:25

And their brethren, in their villages, were to come in every seven days from time to time to be with them:

1 Chronicles 23:3-6

And the Levites were numbered from thirty years old and upward: and their number by their polls, man by man, was thirty and eight thousand.

1 Chronicles 24:3-6

And David with Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, divided them according to their ordering in their service.

1 Chronicles 26:13-16

And they cast lots, as well the small as the great, according to their fathers houses, for every gate.

Luke 1:8-9

Now it came to pass, while he executed the priest's office before God in the order of his course,

Treasury of Scripture Knowledge

Summary

This is the thing that ye shall do; A third part of you entering on the sabbath, of the priests and of the Levites, shall be porters of the doors;

Bible References

Entering

1 Chronicles 23:3
And the Levites were numbered from thirty years old and upward: and their number by their polls, man by man, was thirty and eight thousand.
1 Chronicles 24:3
And David with Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, divided them according to their ordering in their service.
Luke 1:8
Now it came to pass, while he executed the priest's office before God in the order of his course,

Porters

1 Chronicles 26:13
And they cast lots, as well the small as the great, according to their fathers houses, for every gate.

American Standard Version Public Domain