Deuteronomy 6:4-8 (NIV)
4 Hear, O Israel: The Lord our God, the Lord is one.[a] 5 Love the Lord your God with all your heart and with all your soul and with all your strength. 6 These commandments that I give you today are to be on your hearts. 7 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. 8 Tie them as symbols on your hands and bind them on your foreheads.
Matthew 22:34-40 (NIV)
The Greatest Commandment
34 Hearing that Jesus had silenced the Sadducees, the Pharisees got together. 35 One of them, an expert in the law, tested him with this question: 36 “Teacher, which is the greatest commandment in the Law?”
37 Jesus replied: “‘Love the Lord your God with all your heart and with all your soul and with all your mind.’[a] 38 This is the first and greatest commandment. 39 And the second is like it: ‘Love your neighbor as yourself.’[b] 40 All the Law and the Prophets hang on these two commandments.”