"You shall not offer the blood of My sacrifice with leaven, nor shall the sacrifice of the Feast of the Passover be left until morning.
Exodus 34:25
Surrounding context
34:24 For I will cast out the nations before you and enlarge your borders; neither will any man covet your land when you go up to appear before the LORD your God three times in the year.
34:25 "You shall not offer the blood of My sacrifice with leaven, nor shall the sacrifice of the Feast of the Passover be left until morning.
34:26 "The first of the firstfruits of your land you shall bring to the house of the LORD your God. You shall not boil a young goat in its mother's milk."