Exodus 34:17

Lest thou make a covenant with the inhabitants of the land, and they go a whoring after their gods, and do sacrifice unto their gods, and [one] call thee, and thou eat of his sacrifice;

And thou take of their daughters unto thy sons, and their daughters go a whoring after their gods, and make thy sons go a whoring after their gods.

The feast of unleavened bread shalt thou keep. Seven days thou shalt eat unleavened bread, as I commanded thee, in the time of the month Abib: for in the month Abib thou camest out from Egypt.

All that openeth the matrix [is] mine; and every firstling among thy cattle, [whether] ox or sheep, [that is male].