The Reign of Christ. Book Two. Chapter Nine: The First Law: Children Must Be Catechized and Educated for God

And first, just as all by most holy Baptism have been made members of Christ’s Kingdom and then received the covenant of eternal salvation, so Your Royal Majesty will make a law that orders parents to educate and establish their children in Christ’s faith and obedience with great care, with a just penalty appointed for those who themselves infect their children with either false doctrine or bad morals or permit them to be infected by others. Next, it must provide that they diligently make the Church’s catechism known to them when they are old enough to understand it. For unless the foundation of the Church is firmly laid in early childhood through the catechism of Christ, its upbuilding will proceed very poorly from then on. For those who do not labor with utmost zeal to instruct and train those whom they have consecrated to Christ the Lord in Baptism expose themselves to dire retribution. For those who neglect this when it is in their control snatch back the children whom they have consecrated to the Lord and hand them over to the dominion of Satan.