Joshua 23:7-13

7 that you not come 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 down yourselves to them;  8 but cleave to Yahweh your God, as you have done to this day.  9 For Yahweh has driven out from before you great nations and strong: but as for you, no man has stood before you to this day.  10 One man of you shall chase a thousand; for Yahweh your God, he it is who fights for you, as he spoke to you.  11 Take good heed therefore to yourselves, that you love Yahweh your God.  12 Else if you do at all go back, and cleave to the remnant of these nations, even these who remain among you, and make marriages with them, and go in to them, and they to you;  13 know for a certainty that Yahweh your God will no more drive these nations from out of your sight; but they shall be a snare and a trap to you, and a scourge in your sides, and thorns in your eyes, until you perish from off this good land which Yahweh your God has given you.