Exodus 23:14-15

14Three times each year, you must eat a feast to give me honour.

15Eat the Feast of Flat Bread every year. For seven days, you must eat bread that you have made without any yeast. I have commanded you to do this. Do it at the right time during the month Abib. It was in that month that you came out of Egypt. Nobody must come to me without an offering.