And thou shalt {c} teach them diligently to thy children, and shalt talk of them when thou sittest in thy house, and when thou walkest by the way, and when thou liest down, and when thou risest up. {teach: Heb. whet, or, sharpen}

(c) Some read, You shall whet them upon your children: that is, that they may imprint them more deeply in their memory.

Wesley's Notes

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.

King James Translators' Notes

teach: Heb. whet, or, sharpen

Matthew Henry's Concise Commentary

6:6-16 Here are means for maintaining and keeping up religion in our hearts and houses. 1. Meditation. God's words must be laid up in our hearts, that our thoughts may be daily employed about them. 2. The religious education of children. Often repeat these things to them. Be careful and exact in teaching thy children. Teach these truths to all who are any way under thy care. 3. Pious discourse. Thou shalt talk of these things with due reverence and seriousness, for the benefit not only of thy children, but of thy servants, thy friends and companions. Take all occasions to discourse with those about thee, not of matters of doubtful disputation, but of the plain truths and laws of God, and the things that belong to our peace. 4. Frequent reading of the word. God appointed them to write sentences of the law upon their walls, and in scrolls of parchment to be worn about their wrists. This seems to have been binding in the letter of it to the Jews, as it is to us in the intent of it; which is, that we should by all means make the word of God familiar to us; that we may have it ready to use upon all occasions, to restrain us from sin, and direct us in duty. We must never be ashamed to own our religion, nor to own ourselves under its check and government. Here is a caution not to forget God in a day of prosperity and plenty. When they came easily by the gift, they would be apt to grow secure, and unmindful of the Giver. Therefore be careful, when thou liest safe and soft, lest thou forget the Lord. When the world smiles, we are apt to make court to it, and expect our happiness in it, and so we forget Him who is our only portion and rest. There is need of great care and caution at such a time. Then beware; being warned of your danger, stand upon your guard. Thou shalt not tempt the Lord thy God; neither by despairing of his power and goodness, while we keep in the way of our duty; nor by presuming upon it, when we turn aside out of that way.