Know for a certainty that the LORD your God will no more drive out any of these nations from before you; but they shall be snares and traps unto you, and scourges in your sides, and thorns in your eyes, until ye perish from off this good land which the LORD your God hath given you. They shall be snares - לפח lephach, a net or gin, set by the artful fowler to catch heedless birds.
And traps - מוקש mokesh, any snare, toil, or trap, placed on the ground to catch the unwary traveler or wild beast by the foot.
Scourges in your sides, and thorns in your eyes - Nothing can be conceived more vexatious and distressing than a continual goad in the side, or thorn in the eye. They will drive you into obedience to their false gods, and put out the eyes of your understandings by their idolatries. And God will preserve them merely to distress and punish you.