Let not them depart from thine eyes - Never forget that God, who is the author of nature, directs and governs it in all things; for it is no self-determining agent.
Keep sound wisdom and discretion - ומזמה תושיה tushiyah umezimmah . We have met with both these words before. Tushiyah is the essence or substance of a thing; mezimmah is the resolution or purpose formed in reference to something good or excellent. To acknowledge God as the author of all good, is the tushiyah, the essence, of a godly man's creed; to resolve to act according to the directions of his wisdom, is the mezimmah, the religious purpose, that will bring good to ourselves and glory to God. These bring life to the soul, and are ornamental to the man who acts in this way, Proverbs 3:22.
Let not them depart - i. e., The wisdom and discretion of the following clause. Keep thine eye on them, as one who watches over priceless treasures.