“Israel, remember this! The LORD—and the LORD alone—is our God. Love the LORD your God with all your heart, with all your soul, and with all your strength.  Never forget these commands that I am giving you today.  Teach them to your children. Repeat them when you are at home and when you are away, when you are resting and when you are working.  Tie them on your arms and wear them on your foreheads as a reminder. Write them on the doorposts of your houses and on your gates.”

Deuteronomy 6:4-9