“And these words, which I command thee this day, shall be in thine heart:”
King James Version (KJV)
6:5 And thou shalt love the Lord thy God with all thine heart - And is this only an external commandment? Can any then say, that the Sinai - covenant was merely external? With all thy heart - With an entire love. He is One; therefore our hearts must be united in his love. And the whole stream of our affections must run toward Him. O that this love of God may be shed abroad in our hearts.
6:7 Teach them diligently - Heb. whet, or sharpen them, so as they may pierce deep into their hearts. This metaphor signifies the manner of instructing them, that it is to be done diligently, earnestly, frequently, discreetly.
6:8 Thou shalt bind them - Thou shalt give all diligence, and use all means to keep them in thy remembrance, as men often bind something upon their hands, or put it before their eyes to prevent forgetfulness of a thing which they much desire to remember.