Augustine, On the Gift of Perseverance: A few quotes

For there are three points, as you know, which the catholic Church chiefly maintains against them. One of these is, that the grace of God is not given according to our merits; because even every one of the merits of the righteous is God’s gift, and is conferred by God’s grace. The second is, that no one lives in this corruptible body, however righteous he may be, without sins of some kind. The third is, that man is born obnoxious to the first man’s sin, and bound by the chain of condemnation, unless the guilt which is contracted by generation be loosed by regeneration. (2.4)

Now, moreover, when the saints say, “Lead us not into temptation, but deliver us from evil,” what do they pray for but that they may persevere in holiness? For, assuredly, when that gift of God is granted to them,—which is sufficiently plainly shown to be God’s gift, since it is asked of Him,—that gift of God, then, being granted to them that they may not be led into temptation, none of the saints fails to keep his perseverance in holiness even to the end. For there is not any one who ceases to persevere in the Christian purpose unless he is first of all led into temptation. If, therefore, it be granted to him according to his prayer that he may not be led, certainly by the gift of God he persists in that sanctification which by the gift of God he has received. (5.9)

For nothing comes to pass except what either He Himself does, or Himself allows to be done. (6.12)

If, then, there were no other proofs, this Lord’s Prayer alone would be sufficient for us on behalf of the grace which I am defending; because it leaves us nothing wherein we may, as it were, glory as in our own, since it shows that our not departing from God is not given except by God, when it shows that it must be asked for from God. (7.13)

Let us not then be ungrateful, that according to the good pleasure of His will a merciful God delivers so many to the praise of the glory of His grace from such deserved perdition; as, if He should deliver no one therefrom, He would not be unrighteous. Let him, therefore, who is delivered love His grace. (8.16)