1. Those therefore who, made prudent by the participation of prudence, draw near to their God not with feet but with holy morals, on that side by which they are prudent through God's gift, can perish neither by their own nor by another's sin; but on that account, because their prudence is not yet so perfect as it will be in that life, where to those living perfectly no error will be able at all to creep in—even the prudent sometimes acquiesce in deceiving sins; not depraved by their will, but, as men, fallen through human error; and not yet perfected in the full reception of prudence and wisdom, as they will be there, where they can neither be ignorant of anything nor sin any more.
But here, if a rightly-done deed could be perfectly distinguished from sin, that man would never have prayed to be cleansed from his hidden faults, who says: Cleanse me from my hidden sins, O Lord, and from those of others spare Thy servant (Ps. xviii. 13). By which words he sufficiently shows that even those who live holily through the gift of the Holy Spirit, nevertheless, on account of certain human infirmities which they bear, whether knowingly or unknowingly, sometimes either yield to their own sin or consent to another's. In this life, therefore, where men sin either by will, or by error, or by infirmity, whosoever, divinely aided, do not sin by will, assuredly live blamelessly.
But because error or infirmity can involve them in sins, let them faithfully ask to be illuminated and healed by Him, to whom that man exultingly cried out in the Spirit, saying: The Lord is my light and my salvation; whom shall I fear? (Ps. xxvi. 1): so that when the illumination, conferred through the gift of prudence and wisdom, shall have removed the blindness, and the salvation, poured back through the grace of God, shall have healed the languor, then the mind, divinely illuminated and healed, may not be deceived by human error in those things which are to be avoided or to be sought—so as either to defend the false instead of the true, or to reject the true instead of the false; and, without any obstacle of infirmity, may prevail to fulfill the good which it has chosen. 3.
But the salvation of this life, in which we live mortally, is one thing; the salvation of that life, where our mortal shall be endowed with immortality, is another; and in one way we have been made safe in hope, in another way we shall be safe in reality. Here we have been made safe in such a way that we can still perish; there, whoever shall have been safe will be able to perish no more; and on this account, the knowledge which affords us the cognition of things while we live in the night of this age, compared with the fullness to come, is to be believed a part of knowledge, not the whole. On account of which the holy Apostle says: For we know in part, and we prophesy in part; but when that which is perfect shall have come, that which is in part shall be done away (1 Cor. xiii. 9 and 10). Here he asserts that it is done away, that it is consummated:
since indeed that part of knowledge which is to be perfected is not to be done away with for the perfect, but to be fulfilled. Accordingly, where there shall be the full salvation of all the faithful Catholics, no corruptibility, and a blessed immortality, there shall be the true perfection of prudence and wisdom, and the whole knowledge of all things, when knowledge shall have been brought to perfection by the doing away of the part.