2 Kings (Author Compiled by Isaiah and Jeremiah from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
Chapter 11
5And he commanded them, saying, This is the thing that ye shall do; A third part of you that enter in on the sabbath shall even be keepers of the watch of the king's house;
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.