This is a suitable moment for us to exhort especially heads of families to govern their households according to these precepts, and to educate their children from their earliest years. The family may be regarded as the cradle of civil society, and it is in great measure within the circle of family life that the destiny of the State is fostered.
Consequently, they who would break away from Christian discipline are working to corrupt family life, and to destroy it utterly, root and branch. From such an unholy purpose, they are not deterred by the fact that they are inflicting a cruel outrage on parents, who have the right from nature to educate those whom they begot, a right to which is joined the duty of harmonizing instruction and education with the end [purpose] for which they were given their children by the goodness of God.
It is then incumbent upon parents to make every effort to resist attacks on this point and to vindicate at any cost the right to direct the education of their offspring in a Christian manner; and first and foremost, to keep them away from schools where there is risk of their being imbued with the poison of impiety.
Where the right education of youth is concerned, no amount of trouble and labor is too much… However, let everyone be firmly convinced, first of all, that the minds of children are best trained above all by the teaching they receive at home. If in their growing years, they find in their homes the rule of an upright life, and the exercise of Christian virtue, the salvation of society will be in great part assured.
Pope Leo XIII
Sapientiae Christianae