Moses said to the people, “Remember this day which is the day that you came out of Egypt, out of the place you were slaves, because the LORD acted with power to bring you out of there. No leavened bread may be eaten.
References for Exodus 13:3
Today, in the month of Abib, you are going to leave.
References for Exodus 13:4
The LORD will bring you to the land of the Canaanites, the Hittites, the Amorites, the Hivites, and the Jebusites. It is the land that the LORD promised your ancestors to give to you, a land full of milk and honey. You should perform this ritual in this month.
You must eat unleavened bread for seven days. The seventh day is a festival to the LORD.
Only unleavened bread should be eaten for seven days. No leavened bread and no yeast should be seen among you in your whole country.
You should explain to your child on that day, ‘It's because of what the LORD did for me when I came out of Egypt.'
“It will be a sign on your hand and a reminder on your forehead so that you will often discuss the LORD's Instruction, for the LORD brought you out of Egypt with great power.
So you should follow this regulation at its appointed time every year.