This is from Adam Clarke’s commentary on Deuteronomy 6:6 and 8
And these words that I command you today shall be on your heart.
You shall bind them as a sign on your hand and they shall be as frontlets between your eyes.
He is asking the question “Did you ever write something on your hand?”
Is not this an allusion to an ancient and general custom observed in almost every part of the world? When a person wishes to remember a thing of importance, and is afraid to trust to the common operations of memory, he ties a knot on some part of his clothes, or a cord on his hand or finger, or places something out of its usual order, and in view, that his memory may be whetted to recollection, and his eye affect his heart. God, who knows how slow of heart we are to understand, graciously orders us to make use of every help, and through the means of things sensible, to rise to things spiritual.
RBC – Do whatever it takes to keep the Word of God in your mind and heart!
Use any and every means of the ordinary, physical, sensible and temporal in order to advance in the spiritual and eternal.
Write it down, tape it up, play it in your ear buds, carry it in your pocket.
Wear your Bible out. Skim it all the way through. Study it slowly bit by bit.
Read it and memorize it and meditate on it until you remember it.
Live it out.