Exodus 13:2-3

2He said, ‘Keep every firstborn male separate and special for me. Every male who is the first to be born of his mother is mine. He is mine, whether he is man or animal.’

3Moses said to the people, ‘Remember this day, the day when you came out of Egypt. You left the place where you were slaves. The Lord brought you out with his powerful authority. Remember! Do not eat anything that has yeast in it on this day.