Fourth Book of Kings (Author Compiled by Isaias and Jeremias from records of Nathan, Gad, Addo, Ahias, Jehu and others.)
20:6et addam diebus tuis quindecim annos sed et de manu regis Assyriorum liberabo te et civitatem hanc et protegam urbem istam propter me et propter David servum meum
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.