Second Book of Paralipomenon (Author Compiled by Isaias and Esdras from records of Nathan, Gad, Addo, Ahias, Jehu and others.)
Chapter 23
7Levitae autem circumdent regem habentes singuli arma sua et si quis alius ingressus fuerit templum interficiatur sintque cum rege et intrante et egrediente
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.