You shall keep the Feast of Unleavened Bread (you shall eat unleavened bread seven days, as I commanded you, at the time appointed in the month of Abib, for in it you came out of Egypt; none shall appear before Me empty);
Exodus 23:15
Surrounding context
23:14 "Three times you shall keep a feast to Me in the year:
23:15 You shall keep the Feast of Unleavened Bread (you shall eat unleavened bread seven days, as I commanded you, at the time appointed in the month of Abib, for in it you came out of Egypt; none shall appear before Me empty);
23:16 and the Feast of Harvest, the firstfruits of your labors which you have sown in the field; and the Feast of Ingathering at the end of the year, when you have gathered in the fruit of your labors from the field.