Bind them upon thy fingers - See on Proverbs 3:3; (note).
Matthew Henry
Concise Bible Commentary
We must lay up God's commandments safely. Not only, Keep them, and you shall live; but, Keep them as those that cannot live without them. Those that blame strict and careful walking as needless and too precise, consider not that the law is to be kept as the apple of the eye; indeed the law in the heart is the eye of the soul. Let the word of God dwell in us, and so be written where it will be always at hand to be read. Thus we shall be kept from the fatal effects of our own passions, and the snares of Satan. Let God's word confirm our dread of sin, and resolutions against it.
SDA Bible Commentary (limited)
Volume 1-7
3. Upon thy fingers. Hence always within view and serving as a constant reminder (see Deut. 6:8; 11:18).