Joshua 23:12
“Else if ye do in any wise go back, and cleave unto the remnant of these nations, even these that remain among you, and shall make marriages with them, and go in unto them, and they to you:”
One man of you shall chase a thousand: for the Lord your God, he it is that fighteth for you, as he hath promised you.
Take good heed therefore unto yourselves, that ye love the Lord your God.
Else if ye do in any wise go back, and cleave unto the remnant of these nations, even these that remain among you, and shall make marriages with them, and go in unto them, and they to you:
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.
And, behold, this day I am going the way of all the earth: and ye know in all your hearts and in all your souls, that not one thing hath failed of all the good things which the Lord your God spake concerning you; all are come to pass unto you, and not one thing hath failed thereof.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Related Verses
“That ye come not among these nations, these that remain among you; neither make mention of the name of their gods, nor cause to swear by them, neither serve them, nor bow yourselves unto them:”
“When ye have transgressed the covenant of the Lord your God, which he commanded you, and have gone and served other gods, and bowed yourselves to them; then shall the anger of the Lord be kindled against you, and ye shall perish quickly from off the good land which he hath given unto you.”
“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.”
“Take heed to thyself, lest thou make a covenant with the inhabitants of the land whither thou goest, lest it be for a snare in the midst of thee:”
“Now therefore put away, said he, the strange gods which are among you, and incline your heart unto the Lord God of Israel.”