sometimes by particular synods, sometimes by the use of other means which Divine Providence put in their way,—defined that those things should be held firm which they had thus learnt, under God's assistance, to be in accordance with Holy Scripture and apostolical traditions. For the Holy Spirit was not promised to the successors of St. Peter, that by His revelation they might make known a new doctrine, but that by His assistance they might holily preserve and faithfully expound the revelation delivered to the Apostles, or, in other words, the "deposit of the faith" (depositum fidei). This is that apostolical doctrine which all the venerable Fathers of the Church have embraced, and all the orthodox holy Doctors have venerated and followed; for they had the most perfect conviction that this holy See of Peter always, remains free from all error, according to the divine promise of our Lord and Saviour, which He made to the prince of His disciples: "I have prayed for thee, that thy faith fail not; and thou, in thy turn one day,[1] strengthen thy brethren."
This gracious gift of the truth and of indefectible faith has been accordingly given by God to Peter and his successors in this See, that they might discharge their high office to the salvation of all; that so the universal flock of Christ, turned from the poisonous allurements of error, might be nourished by the pasture of heavenly doctrine; so that, all occasion of schism having been removed, the whole Church might be preserved in unity, and, resting on its own solid basis, might stand fast against the gates of hell.
