Exodus 13:8-10

8And you shall tell your son in that day, saying, ‘This is done because of what the Lord did for me when I came up from Egypt.’

9It shall be as a sign to you on your hand and as a memorial between your eyes, that the Lord’s law may be in your mouth; for with a strong hand the Lord has brought you out of Egypt.

10You shall therefore keep this ordinance in its season from year to year.