Hear, O Israel: The Lord our God, the Lord is one.  Love the Lord your God with all your heart and with all your soul and with all your strength.  These commandments that I give you today are to be on your hearts.  Impress them on your children. Talk about them when you sit at home and when you walk along the road, when you lie down and when you get up.  Tie them as symbols on your hands and bind them on your foreheads.

Deuteronomy 6:4-8