Consider this:

A public-school system, if it means the providing of free education for those who desire it, is a noteworthy and beneficent achievement of modern times; but when once it becomes monopolistic it is the most perfect instrument of tyranny which has yet been devised. Freedom of thought in the middle ages was combated by the Inquisition, but the modern method is far more effective. Place the lives of children in their formative years, despite the convictions of their parents, under the intimate control of experts appointed by the state, force them to attend schools where the higher aspirations of humanity are crushed out, and where the mind is filled with the materialism of the day, and it is difficult to see how even the remnants of liberty can subsist. Such a tyranny, supported as it is by a perverse technique used as the instrument in destroying human souls, is certainly far more dangerous than the crude tyrannies of the past, which despite their weapons of fire and sword permitted thought at least to be free (14).

That is taken from Christianity and Liberalism, one of the most well-known works of the early twentieth century American Presbyterian, J. Gresham Machen, a book which I am in the process of reading for a class. While the words are harsh, they are disturbingly true. This is why parents need to be determined and active in educating their children, especially with regards to matters of the heart. Neglecting this fundamental responsibility is a grave error (Proverbs 22:6).

While parents are unquestionably the primary teachers of their children, God, in his wisdom, has instituted the community of the Church to aid in the education of children. By engaging them in catechetical instruction, the Church partakes in raising a child in the fear of the Lord. In referring to catechesis, I do not mean mere memorization of various confessions and creeds but rather an extensive program in which children are familiarized with Scripture, doctrine, and some degree of practical theology which enables them to live according to the truths of the faith. I particularly like the words of the Catechism of the Catholic Church on this point:

Catechesis...[includes] especially the teaching of Christian doctrine imparted, generally speaking, in an organic and systematic way, with a view to initiating the hearers into the fullness of Christian life....catechesis is built on a certain number of elements of the Church's pastoral mission...[including] the initial proclamation of the Gospel or missionary preaching to arouse faith; examination of the reasons for belief; experience of Christian living; celebration of the sacraments; integration into the ecclesial community; and apostolic and missionary witness (II, 5-6).

We cannot rely on the state to give our children the necessary foundation to live a life that is directed towards the glory of God. Quite the contrary, in fact, in our age we can expect them to do precisely the opposite. Hence the need for proper education in the home and in the Church, so that us and our posterity might "take captive every thought to make it obedient to Christ" (2 Cor. 10:5). And this, moreover, is one of the principal reasons I wish to be a teacher.