70 Of all that exists on the face of the earth, the soul alone has deathless life. A system of education that should not respect the sacred precincts of the Christian family, protected by God's holy law, that should attack its foundations, bar to the young the way to Christ, to the Savior's fountains of life and joy (cf. Isaias xii. 3), that should consider apostasy from Christ and the Church as a proof of fidelity to the people or a particular class's word: "They that depart from thee, shall be written in the earth" ( Jeremiah xvii. 13).
Source: Summi Pontificatus (Vatican.va)