First Book of Paralipomenon (Author Compiled by Isaias and Esdras from records of Nathan, Gad, Addo, Ahias, Jehu and others.)
28:21ecce divisiones sacerdotum et Levitarum in omne ministerium domus Domini adsistunt tibi et parati sunt et noverunt tam principes quam populus facere omnia praecepta tua
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.