Know for a certainty that the Lord your God will no more
drive out [any] of these nations from before you
Or, "knowing ye shall know" F18; or "know ye"; this may be taken for granted, or the fullest proof, and clearest demonstration, and strongest assurance will be given of it, that in case of such bad conduct, and disobedience to the will of God, no more of the nations of the Canaanites will be driven out of the cities in which they are:
but they shall be snares and traps unto you;
who by their bad examples would draw them both to idolatry and superstitious worship, and into all irreligion, profaneness, and immorality, as they did, ( Psalms 106:35-39 ) ;
and scourges in your sides;
who either, by ensnaring them, would get an advantage over them, and distress them in their persons, families, and estates; or would be the means of the Lord's correcting and chastising them with the rod and stripes of men, for the iniquities these would draw them into; the allusion is to scourges and lashes laid on the sides of men, or to goads with which beasts are pushed on their sides and driven:
and thorns in your eyes;
very troublesome and distressing; for even a mote in the eye is very afflicting: and much more a thorn; (See Gill on Numbers 33:55). Jarchi interprets this word by camps surrounding them, as shields do the bodies of men, and which is approved of by Gussetius F19:
until ye perish from off this good land, which the Lord your God hath
given you;
by sword, famine, pestilence, or captivity, which has been their case.