Deuteronomy 6:1 - 8:20

6:5-9 "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 upon 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. Write them on the doorframes of your houses and on your gates."


There was once a tradition that religious leaders would tie tiny scrolls to their foreheads to follow this command.  This is also where the mezuzah that those of the Jewish faith place on their door frames comes from.  


6:24-25 "The LORD commanded us to obey all these decrees and to fear the LORD our God, so that we might always prosper and be kept alive, as is the case today.  And if we are careful to obey all this law before the LORD our God, as he has commanded us, that will be our righteousness." 

8:6  Observe the commands of the LORD your God, walking in his ways and revering him.

8:20 Like the nations the LORD destroyed before you, so you will be destroyed for not obeying the LORD your God.

The key is obedience.