Second Book of Paralipomenon (Author Compiled by Isaias and Esdras from records of Nathan, Gad, Addo, Ahias, Jehu and others.)
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.