Council of Trent: Session VI, Justification, Chapter XIII

CHAPTER XIII. On the gift of Perseverance.

So also as regards the gift of perseverance, of which it is written, He that shall persevere to the end, he shall be saved:-which gift cannot be derived from any other but Him, who is able to establish him who standeth that he stand perseveringly, and to restore him who falleth:-let no one herein promise himself any thing as certain with an absolute certainty; though all ought to place and repose a most firm hope in God's help. For God, unless men be themselves wanting to His grace, as he has begun the good work, so will he perfect it, working (in them) to will and to accomplish. Nevertheless, let those who think themselves to stand, take heed lest they fall, and, with fear and trembling work out their salvation, in labours, in watchings, in almsdeeds, in prayers and oblations, in fastings and chastity: for, knowing that they are born again unto a hope of glory, but not as yet unto glory, they ought to fear for the combat which yet remains with the flesh, with the world, with the devil, wherein they cannot be victorious, unless they be with God's grace, obedient to the Apostle, who says; We are debtors, not to the flesh, to live according to the flesh; for if you live according to the flesh, you shall die; but if by the spirit you mortify the deeds of the flesh, you shall live.

Translation: J. Waterworth, The Canons and Decrees of the Council of Trent (1848), Hanover Historical Texts Project transcription (1995).