Exodus 34:24-26

New Revised Standard Version, Anglicised Catholic Edition

²⁴ For I will cast out nations before you, and enlarge your borders; no one shall covet your land when you go up to appear before the Lord your God three times in the year.

²⁵ You shall not offer the blood of my sacrifice with leaven, and the sacrifice of the festival of the passover shall not be left until the morning.

²⁶ The best of the first fruits of your ground you shall bring to the house of the Lord your God.

You shall not boil a kid in its mother’s milk.