Nicene and Post-Nicene Fathers, Vol. V:
A Treatise on the Predestination of the...: Chapter 11

Chapter 11.—Effect of Prayer for Perseverance.

But, lest perchance it be said that perseverance even to the end is not indeed lost when it has once been given,—that is, when a man has persevered unto the end,—but that it is lost, in some sense, when a man by contumacy so acts that he is not able to attain to it; just as we say that a man who has not persevered unto the end has lost eternal life or the kingdom of God, not because he had already received and actually had it, but because he would have received and had it if he had persevered;—let us lay aside controversies of words, and say that some things even which are not possessed, but are hoped to be possessed, may be lost. Let any one who dares, tell me whether God cannot give what He has commanded to be asked from Him. Certainly he who affirms this, I say not is a fool, but he is mad. But God commanded that His saints should say to Him in prayer, “Lead us not into temptation.” Whoever, therefore, is heard when he asks this, is not led into the temptation of contumacy, whereby he could or would be worthy to lose perseverance in holiness.