NKJ Deuteronomy 6:4-7 Hear, O Israel: The LORD our God, the LORD is one! 5 You shall love the LORD your God with all your heart, with all your soul, and with all your strength. 6 And these words which I command you today shall be in your heart. 7 You shall teach them diligently to your children, and shall talk of them when you sit in your house, when you walk by the way, when you lie down, and when you rise up.
NKJ Deuteronomy 11:18-19 Therefore you shall lay up these words of mine in your heart and in your soul, and bind them as a sign on your hand, and they shall be as frontlets between your eyes. 19 You shall teach them to your children, speaking of them when you sit in your house, when you walk by the way, when you lie down, and when you rise up.”
NKJ 2 Timothy 3:16-17 All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof [ἐλεγμός, elegmós, noun related to the verb ἐλέγχω, elégchō, used in Heb. 12:5], for correction, for instruction [παιδεία, paideía, same word used in Eph. 6:4 and Heb. 12:5, 7, 8, and 11] in righteousness, 17 that the man of God may be complete, thoroughly equipped for every good work.
You cannot make your children love the Bible, I allow. None but the Holy Spirit can give us a heart to delight in the Word. But you can make your children acquainted with the Bible; and be sure they cannot be acquainted with that blessed book too soon, or too well.
A thorough knowledge of the Bible is the foundation of all clear views of religion. He that is well-grounded in it will not generally be found a waverer, and carried about by every wind of new doctrine. Any system of training which does not make a knowledge of Scripture the first thing is unsafe and unsound.
You have need to be careful on this point just now, for the devil is abroad, and error abounds. Some are to be found among us who give the Church the honor due to Jesus Christ. Some are to be found who make the sacraments saviors and passports to eternal life. And some are to be found in like manner who honor a catechism more than the Bible, or fill the minds of their children with miserable little story-books, instead of the Scripture of truth. But if you love your children, let the simple Bible be everything in the training of their souls; and let all other books go down and take the second place. (The Duties of Parents)
In my view, parents who send their children to public schools – or even to many private Christian schools – will have a much more difficult time instructing their children in the Word of God, for they will have to combat the constant undermining influence of the worldly thinking their children are encountering in a much deeper way. This does not mean, of course, that it is necessarily wrong for parents to send their children to such schools, but it does mean that they should do so only if they are fully aware of the increased spiritual warfare and temptation to which they are submitting them, and only if they are able to combat such things and are committed to doing so. At any rate, we must never forget the supreme importance of the Scriptures in raising our children for the glory of God.