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.

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 - תושיה ומזמה 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.

My son, let not them depart from thine eyes,.... Meaning not the things done by Wisdom; though it is good to contemplate his works of creation and providence, which serve to set forth the glory of Christ, and lead into adoring and admiring views of him, and to thankfulness to him; but wisdom, understanding, and knowledge, whereby these things are done, which are but so many names of Christ: we should always set him before us, keep him always in view, be ever looking to him by faith, and never suffer him to depart from our eyes; we should always have in sight his divine Person for our acceptance with God, the greatness and glory of it to encourage our faith and hope in him; we should keep in view his righteousness for our justification, and which we should ever make mention of at the throne of grace, and hold it forth in the hand of faith against all charges and accusations of law and justice, Satan, or our own hearts; we should be continually looking to his blood for peace and pardon, healing and cleansing; and our eyes should be at all times on his fulness, for fresh supplies of grace, for spiritual food, or the daily bread of our souls, and for spiritual strength and comfort; we should always consider him as the Saviour, and be exercising faith on him as such, for there is no other; and should always look upon him as the Mediator between God and man, and make use of him; and he should be ever before us as our example, both in the exercise of grace and performance of duty, to copy after; and we should always keep sight of him while running our Christian race, as the forerunner for us entered, and as the mark for the prize of the high calling of God. And not only Wisdom, or Christ, but all the things that are said of him in the context, we should never lose sight of; the exceeding great gain got by him, the superlative preciousness of him, the fulness of blessings in both his hands, the pleasantness and peaceableness of his ways, the usefulness of him as a tree of life to those that lay hold upon him and retain him, and the works of nature and providence done by him, Proverbs 3:14. Moreover, this may include all the truths and doctrines of Wisdom, or Christ; for, if the law and its precepts were to be upon the hands and as frontlets between the eyes of the Israelites, and so be ever in sight, then much more the doctrines of the Gospel, Deuteronomy 6:8. It is observable that the Septuagint here makes use of the same word the apostle does in Hebrews 2:1; speaking of Gospel truths; See Gill on Hebrews 2:1; these are meant in the next clause; and some by a transposition place them thus, "let not sound wisdom and discretion depart from thine eyes, keep" them; for by
sound wisdom is meant sound doctrine, the wholesome words of Christ, the solid and substantial truths of the Gospel. The Vulgate Latin version renders it, "keep the law"; but the Syriac version, much better, "keep my doctrine", the doctrine of the Gospel; which also is meant by
discretion, or "counsel" (d), as some render the word, and as the Gospel is called, Acts 20:27; this should be kept; the doctrines of it should be held fast and not let go, or be departed from; and the ordinances of it should be observed and kept, as they were delivered, from a principle of love, and a view to the glory of Christ; the advantages arising from them follow.
(d) Sept. "consilium", Arabic version.

Let us not suffer Christ's words to depart from us, but keep sound wisdom and discretion; then shall we walk safely in his ways. The natural life, and all that belongs to it, shall be under the protection of God's providence; the spiritual life, and all its interests, under the protection of his grace, so that we shall be kept from falling into sin or trouble.

sound wisdom--(compare Proverbs 2:7).
let . . . eyes--that is, these words of instruction.

From this eminence, in which the work of creation presents wisdom, exhortations are now deduced, since the writer always expresses himself only with an ethical intention regarding the nature of wisdom:
21 My son, may they not depart from thine eyes -
Preserve thoughtfulness and consideration,
22 And they will be life to thy soul
And grace to thy neck.
If we make the synonyms of wisdom which are in 21b the subject per prolepsin to אל־ילזוּ (Hitzig and Zckler), then Proverbs 3:19-20 and Proverbs 3:21-22 clash. The subjects are wisdom, understanding, knowledge, which belong to God, and shall from His become the possession of those who make them their aim. Regarding לוּז, obliquari, deflectere, see under Proverbs 2:15, cf. Proverbs 4:21; regarding תּשׁיּה (here defective after the Masora, as rightly in Vened. 1515, 1521, and Nissel, 1662), see at Proverbs 2:7; ילזוּ for תּלזנה, see at Proverbs 3:2. The lxx (cf. Hebrews 2:1) translate without distinctness of reference: υἱὲ μὴ παραῤῥυῂς (παραρυῇς), let it now flow past, i.e., let it not be unobserved, hold it always before thee; the Targ. with the Syr. render לא נזּל, ne vilescat, as if the words were אל־יזוּלוּ. In 22a the synallage generis is continued: ויהיוּ for ותהיינה. Regarding גּרגּרת, see at Proverbs 1:9. By wisdom the soul gains life, divinely true and blessed, and the external appearance of the man grace, which makes him pleasing and gains for him affection.

Eyes - The eyes of thy mind. Constantly and seriously meditate upon them.