Exodus 34:17

15“Don’t make a covenant with the inhabitants of the land, lest they play the prostitute after their gods, and sacrifice to their gods, and one call you and you eat of his sacrifice;

16and you take of their daughters to your sons, and their daughters play the prostitute after their gods, and make your sons play the prostitute after their gods.

17“You shall make no cast idols for yourselves.

18“You shall keep the feast of unleavened bread. Seven days you shall eat unleavened bread, as I commanded you, at the time appointed in the month Abib; for in the month Abib you came out of Egypt.

19“All that opens the womb is mine; and all your livestock that is male, the firstborn of cow and sheep.