What could ever be a sufficient reason for excusing in any way the direct murder of the innocent? This is precisely what we are dealing with here. Whether inflicted upon the mother or upon the child, it is against the precept of God and the law of nature: 'Thou shalt not kill.'
Pope Pius XIThose wretches tainted with the error of Indifferentism and Modernism hold that dogmatic truth is not absolute, but relative: that is, that it must adapt itself to the varying necessities of the times and the varying dispositions of souls, since it is not contained in an unchangeable revelation, but is, by its very nature, meant to accommodate itself to the life of man.
Pope Pius XIFor them (the peoples of the Soviet Union) We cherish the warmest paternal affection. We are well aware that not a few of them groan beneath the yoke imposed on them by men who in very large part are strangers to the real interests of the country. We recognize that many others were deceived by fallacious hopes. We blame only the system with its authors and abettors who considered Russia the best field for experimenting with a plan elaborated years ago, and who from there continue to spread it from one of the world to the other.
Pope Pius XIMan cannot be exempted from his divinely-imposed obligations toward civil society, and the representatives of authority have the right to coerce him when he refuses without reason to do his duty. Society, on the other hand, cannot defraud man of his God-granted right... Nor can society systematically void these rights by making their use impossible.
Pope Pius XIFor they have always unanimously maintained that nature, rather the Creator Himself, has given man the right of private ownership not only that individuals may be able to provide for themselves and their families but also that the goods which the Creator destined for the entire family of mankind may through this institution truly serve this purpose.
Pope Pius XI