You shall write them on the doorposts of your house and on your gates.
Deuteronomy 6:9

The Hebrew word for gate in this verse is sha'ar, which is the same as a word for "to split open, reason out, calculate." The gates were places for breaking things down and reasoning things out. The implication is that we are to meditate on God's Law in all circumstances: at home and in our places of business, in our private lives, and in our courts and halls of government.