The organic constitution of the Church is not immutable; but Christian society, just as human society, is subject to perpetual evolution.
Pope Pius XThe Church alone, being the Bride of Christ and having all things in common with her Divine Spouse, is the depository of the truth.
Pope Pius XBut since the Modernists (as they are commonly and rightly called) employ a very clever artifice, namely, to present their doctrines without order and systematic arrangement into one whole, scattered and disjointed one from another, so as to appear to be in doubt and uncertainty, while they are in reality firm and steadfast, it will be of advantage, Venerable Brethren, to bring their teachings together here into one group, and to point out the connexion between them, and thus to pass to an examination of the sources of the errors, and to prescribe remedies for averting the evil.
Pope Pius XOur Apostolic Mandate requires from Us that We watch over the purity of the Faith and the integrity of Catholic discipline. It requires from Us that We protect the faithful from evil and error; especially so when evil and error are presented in dynamic language which, concealing vague notions and ambiguous expressions with emotional and high-sounding words, is likely to set ablaze the hearts of men in pursuit of ideals which, whilst attractive, are nonetheless nefarious.
Pope Pius XThe proposition that the principal articles of the Apostles' Creed did not have the same meaning for the Christians of the earliest times as they have for Christians of our time is hereby condemned and proscribed as erroneous.
Pope Pius XIt is impossible to approve in Catholic publications of a style inspired by unsound novelty which seems to deride the piety of the faithful and dwells on the introduction of a new order of Christian life, on new directions of the Church, on new aspirations of the modern soul, on a new vocation of the clergy, on a new Christian civilisation.
Pope Pius X