Exodus 23:17-19

Amplified Bible

¹⁷Three times a year all your males shall appear before the ^[a]Lord God.

¹⁸“You shall not offer the blood of My sacrifice with ^[b]leavened bread; and the fat of My feast is not to be left overnight until morning.

¹⁹“You shall bring the choice first fruits of your ground into the house of the Lord your God.

“You shall not ^[c]boil a young goat in its mother’s milk.

Exodus 23:17 “Lord” with only an initial capital is Heb Adonai (Master); “God” (all caps) represents YHWH (Yahweh) and is usually rendered “Lord” (all caps).
Exodus 23:18 Because leaven is a kind of fungus, it became a symbol of corruption and sin. But in some contexts it had positive connotations (e.g. Lev 23:17; Matt 13:33).
Exodus 23:19 This may have been a pagan practice, perhaps a fertility rite.