The Vatican Council
DOGMATIC CONSTITUTION ON THE CATHOLIC FAITH - April 24th, 1870
Pius, bishop, servant of the servants of God, with the approval of the sacred council, for an everlasting record.
The Son of God, redeemer of the human race, our lord Jesus Christ, promised, when about to return to his heavenly Father, that he would be with this church militant upon earth all days even to the end of the world  . Hence never at any time has he ceased to stand by his beloved bride, assisting her when she teaches, blessing her in her labours and bringing her help when she is in danger. Now this redemptive providence appears very clearly in unnumbered benefits, but most especially is it manifested in the advantages which have been secured for the christian world by ecumenical councils, among which the council of Trent requires special mention, celebrated though it was in evil days. Thence came a closer definition and more fruitful exposition of the holy dogmas of religion and the condemnation and repression of errors; thence too, the restoration and vigorous strengthening of ecclesiastical discipline, the advancement of the clergy in zeal for learning and piety, the founding of colleges for the training of the young for the service of religion; and finally the renewal of the moral life of the christian people by a more accurate instruction of the faithful, and a more frequent reception of the sacraments. What is more, thence also came a closer union of the members with the visible head, and an increased vigour in the whole mystical body of Christ. Thence came the multiplication of religious orders and other organisations of christian piety; thence too that determined and constant ardour for the spreading of Christ's kingdom abroad in the world, even at the cost of shedding one's blood.
While we recall with grateful hearts, as is only fitting, these and other outstanding gains, which the divine mercy has bestowed on the church especially by means of the last ecumenical synod, we cannot subdue the bitter grief that we feel at most serious evils, which have largely arisen either because the authority of the sacred synod was held in contempt by all too many, or because its wise decrees were neglected. Everybody knows that those heresies, condemned by the fathers of Trent, which rejected the divine magisterium of the church and allowed religious questions to be a matter for the judgment of each individual, have gradually collapsed into a multiplicity of sects, either at variance or in agreement with one another; and by this means a good many people have had all faith in Christ destroyed.
Indeed even the holy Bible itself, which they at one time claimed to be the sole source and judge of the christian faith, is no longer held to be divine, but they begin to assimilate it to the inventions of myth. Thereupon there came into being and spread far and wide throughout the world that doctrine of rationalism or naturalism, - utterly opposed to the christian religion, since this is of supernatural origin, - which spares no effort to bring it about that Christ, who alone is our lord and saviour, is shut out from the minds of people and the moral life of nations. Thus they would establish what they call the rule of simple reason or nature. The abandonment and rejection of the christian religion, and the denial of God and his Christ, has plunged the minds of many into the abyss of pantheism, materialism and atheism, and the consequence is that they strive to destroy rational nature itself, to deny any criterion of what is right and just, and to overthrow the very foundations of human society.
With this impiety spreading in every direction, it has come about, alas, that many even among the children of the catholic church have strayed from the path of genuine piety, and as the truth was gradually diluted in them, their catholic sensibility was weakened. Led away by diverse and strange teachings  and confusing nature and grace, human knowledge and divine faith, they are found to distort the genuine sense of the dogmas which holy mother church holds and teaches, and to endanger the integrity and genuineness of the faith. At the sight of all this, how can the inmost being of the church not suffer anguish? For just as God wills all people to be saved and come to the knowledge of the truth  , just as Christ came to save what was lost  and to gather into one the children of God who were scattered abroad , so the church, appointed by God to be mother and mistress of nations, recognises her obligations to all and is always ready and anxious to raise the fallen, to steady those who stumble, to embrace those who return, and to strengthen the good and urge them on to what is better. Thus she can never cease from witnessing to the truth of God which heals all  and from declaring it, for she knows that these words were directed to her: My spirit which is upon you, and my words which I have put in your mouth, shall not depart out of your mouth from this time forth and for evermore .
And so we, following in the footsteps of our predecessors, in accordance with our supreme apostolic office, have never left off teaching and defending catholic truth and condemning erroneous doctrines. But now it is our purpose to profess and declare from this chair of Peter before all eyes the saving teaching of Christ, and, by the power given us by God, to reject and condemn the contrary errors. This we shall do with the bishops of the whole world as our co-assessors and fellow-judges, gathered here as they are in the Holy Spirit by our authority in this ecumenical council, and relying on the word of God in scripture and tradition as we have received it, religiously preserved and authentically expounded by the catholic church.
3. See Mt 28, 20.
4. See Heb 13, 9
5. 1 Tm 2, 4.
6. Lk 19, 10.
7. Jn 11, 52.
8. See Wis 16, 12
9. Is 59, 21