Joshua 23:6-8

So be very strong and steadfast; be careful to obey fully what is written in the Scroll of the teaching of Moses, without deviating from it. Do not intermingle with the nations that are left among you nor speak the names of their gods when you take an oath. And by all means don’t worship or pray to them. As you have done until now, cling tightly to YAHWEH, for he is your God.