2 Chronicles 23:4

This is the thing that ye must do: A third part of you, those who enter on the sabbath, shall be porters at the doors with the priests and the Levites;

1 Chronicles 9:25

And their brethren, who were in their villages, came every seven days in their set times with them.

1 Chronicles 23:3-6

were numbered from the age of thirty years and upward; and their number by their polls, man by man, was thirty-eight thousand.

1 Chronicles 24:3-6

And David distributed them, Zadok being of the sons of Eleazar, and Ahimelech of the sons of Ithamar, according to their turns in their ministry.

1 Chronicles 26:13-16

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

Luke 1:8-9

And it came to pass that 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
were numbered from the age of thirty years and upward; and their number by their polls, man by man, was thirty-eight thousand.
1 Chronicles 24:3
And David distributed them, Zadok being of the sons of Eleazar, and Ahimelech of the sons of Ithamar, according to their turns in their ministry.
Luke 1:8
And it came to pass that while he executed the priest's office before God in the order of his course,

Porters

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