1 Samuel 27:10

Against the south of Judah: these and the following words are ambiguous; for they may be understood, either of the southern parts from Judah, &c., which he would have Achish understand; or of another country lying southward from Judah, &c., which David meant, and which was the truth. So though it was not a downright lie; yet it was an equivocation, with an intention to deceive, which is the formality of a lie, and was contrary to that simplicity which became David, both as a prince, and as an eminent professor of the true religion. And against, for that is against; for in the following words he particularly expresseth what part of the south of Judah he went against, even that which was inhabited by the Jerahmeelites, and by the Kenites. The Jerahmeelites; the posterity of Hezron, a family of Judah, 1 Chronicles 2:9,25. The Kenites; the posterity of Jethro, which chose to dwell in the south of Judah, Judges 1:16. See Numbers 24:21.