I’ve devoted a number of posts to demonstrating the folly of Protestant attempts to paint St Augustine with their own colors. In short: it cannot be done—not, at any rate, if one wishes to avoid running his works through a shredder and pulling out tiny little bits that have that Geneva ring to them when you turn up the music really loud. Okay, I’m going bonkers with the metaphor-mixing. Let’s move on.
Here is yet another small snippet showing the unambiguously Catholic character of his writings. St Augustine opens the Soliloquies with a prayer, part of which go like this:
God, through whom we disapprove the error of those, who think that there are no merits of souls before You. God, through whom it comes that we are not in bondage to the weak and beggarly elements. God, who cleanses us, and prepares us for Divine rewards, to me propitious come Thou. [I, 3; emphasis added]
This passage flatly contradicts the Protestant errors that there is no sense at all in which we merit anything but condemnation from God, and that there is no sense at all in which we could be said to receive rewards from Him.
In the very next section of this opening prayer, he writes:
God, by whose ever-during laws the stable motion of shifting things is suffered to feel no perturbation, the thronging course of circling ages is ever recalled anew to the image of immovable quiet: by whose laws the choice of the soul is free, and to the good rewards and to the evil pains are distributed by necessities settled throughout the nature of everything. [I, 4; emphasis added]
This passage repeats the fact that the good will be rewarded, just in case we didn’t get the point the first time. And it adds the extra observation that man’s will is not in bondage in the way that at least some Protestants think. He doesn’t discuss the reasons for these facts in this context, but we have seen elsewhere (here, for one example) why he says so. In short: if we do not have free will, or if God does not reward the good, then He is not just. But this is obviously impossible. Consequently it is the Protestant claims to the contrary that are in error.
St Augustine doesn’t get this wrong. He wasn’t some crypto-proto-Protestant. He was Catholic. He wouldn’t be a Doctor of the Church if he wasn’t. That very fact really ought to induce Protestant hangers-on to think seriously about how they view his teaching.
Edit: It is probably necessary (unfortunately) to respond to the suggestion that St Augustine wrote the Soliloquies early in his career and that consequently it supposedly does not reflect his mature thought. The problem with this is that the Retractations related to this work say nothing about rejecting the ideas I've quoted here. The portion of the Retractations related to the Soliloquies is included in this edition of his works (pp. 17-18), and it says nothing whatsoever about these ideas. It is therefore unreasonable to suppose that he rejected free will or merits later in life.