Second Book of Kings (Author Compiled by Isaias from records of Samuel, David, Nathan, and Gad.)
3:18nunc ergo facite quoniam Dominus locutus est ad David dicens in manu servi mei David salvabo populum meum Israhel de manu Philisthim et omnium inimicorum eius
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.