Exodus 23:16-19New Revised Standard Version (NRSV)
16 You shall observe the festival of harvest, of the first fruits of your labor, of what you sow in the field. You shall observe the festival of ingathering at the end of the year, when you gather in from the field the fruit of your labor. 17 Three times in the year all your males shall appear before the Lord God.
18 You shall not offer the blood of my sacrifice with anything leavened, or let the fat of my festival remain until the morning.
19 The choicest of the first fruits of your ground you shall bring into the house of the Lord your God.
You shall not boil a kid in its mother’s milk.