Joshua 23:6-13

6Be very strong, then, so that you can keep and obey all that is written in the Book of the Law of Moses, not turning aside from it to the right or to the left. 7So you are not to associate with these nations that remain among you. You must not call on the names of their gods or swear by them, and you must not serve them or bow down to them. 8Instead, you shall hold fast to the LORD your God, as you have done to this day.

9The LORD has driven out great and powerful nations before you, and to this day no one can stand against you. 10One of you can put a thousand to flight, because the LORD your God fights for you, just as He promised. 11Therefore watch yourselves carefully, that you love the LORD your God. 12For if you turn away and cling to the rest of these nations that remain among you, and if you intermarry and associate with them, 13know for sure that the LORD your God will no longer drive out these nations before you. Instead, they will become for you a snare and a trap, a scourge in your sides and thorns in your eyes, until you perish from this good land that the LORD your God has given you.