Protestants appeal to St Augustine more than to any other Early Church Father (by far). This is because, since the time of Luther, Protestants believe St Augustine was more or less "Protestant," and thus a strong (historical) ally against the Catholic Church. The fact is, nothing could be further from the truth, and while Protestants might think St Augustine was on their side, the evidence points conclusively to the contrary.
The following are some quotes that The Supplement blog posted, revealing St Augustine actually taught some pretty "Catholic" things - things that wouldn't sit well with Protestant doctrine. And what's most amazing is that these quotes are all taken from St Augustine's best known work, The Confessions - a book which is ironically highly praised by Protestants.
Speaking on Baptism (all links to original Supplement posts, with expanded commentary):
And hereby, in Your Word, not the depth of the sea, but the earth parted from the bitterness of the waters, brings forth not the creeping and flying creature that has life, but the living soul itself. For now has it no longer need of baptism, as the heathen have, and as itself had when it was covered with the waters—for no other entrance is there into the kingdom of heaven, since You have appointed that this should be the entrance [Confessions XIII.21, emphasis added]Again on Baptism:
And Your purposes were profoundly impressed upon me; and, rejoicing in faith, I praised Your name. And that faith suffered me not to be at rest in regard to my past sins, which were not yet forgiven me by Your baptism. [Confessions, IX.4]
Baptism yet again:
Quickly did You remove his life [i.e., that of St. Augustine’s son Adeodatus] from the earth; and now I recall him to mind with a sense of security, in that I fear nothing for his childhood or youth, or for his whole self. We took him coeval with us in Your grace, to be educated in Your discipline; and we were baptized, and solicitude about our past life left us. [ibid., IX.6]
Although [Nebridius] also, not being yet a Christian, had fallen into the pit of that most pernicious error of believing Your Son to be a phantasm, yet, coming out thence, he held the same belief that we did; not as yet initiated in any of the sacraments of Your Church, but a most earnest inquirer after truth. Whom, not long after our conversion and regeneration by Your baptism, he being also a faithful member of the Catholic Church, and serving You in perfect chastity and continency among his own people in Africa, when his whole household had been brought to Christianity through him, You released from the flesh; and now he lives in Abraham's bosom. [Confessions, IX.3; emphasis added]Speaking on the Eucharist:
For He judges and approves what He finds right, but disapproves what He finds amiss, whether in the celebration of those sacraments by which are initiated those whom Your mercy searches out in many waters; or in that in which the Fish Itself is exhibited, which, being raised from the deep, the devout earth feeds upon… [Confessions, XIII.23; emphasis added]Speaking on Prayers for the Dead:
I know that she acted mercifully, and from the heart forgave her debtors their debts; do Thou also forgive her debts, whatever she contracted during so many years since the water of salvation. Forgive her, O Lord, forgive her, I beseech You; enter not into judgment with her. Let Your mercy be exalted above Your justice, because Your words are true, and You have promised mercy unto the merciful; which You gave them to be who wilt have mercy on whom You will have mercy, and wilt have compassion on whom You have had compassion. [Confessions IX.13; emphasis added]Speaking on Mass for the Dead:
So, when the body was carried forth, we both went and returned without tears. For neither in those prayers which we poured forth unto You when the sacrifice of our redemption was offered up unto You for her—the dead body being now placed by the side of the grave, as the custom there is, prior to its being laid therein—neither in their prayers did I shed tears; yet was I most grievously sad in secret all the day, and with a troubled mind entreated You, as I was able, to heal my sorrow, but You did not; fixing, I believe, in my memory by this one lesson the power of the bonds of all habit, even upon a mind which now feeds not upon a fallacious word. [Confessions IX.12; emphasis added]Speaking on Holy Relics:
Thou by a vision made known to Your renowned bishop [St. Ambrose – RdP] the spot where lay the bodies of Gervasius and Protasius, the martyrs (whom You had in Your secret storehouse preserved uncorrupted for so many years), whence You might at the fitting time produce them to repress the feminine but royal fury. For when they were revealed and dug up and with due honour transferred to the Ambrosian Basilica, not only they who were troubled with unclean spirits (the devils confessing themselves) were healed, but a certain man also, who had been blind many years, a well-known citizen of that city, having asked and been told the reason of the people's tumultuous joy, rushed forth, asking his guide to lead him there. Arrived there, he begged to be permitted to touch with his handkerchief the bier of Your saints, whose death is precious in Your sight. When he had done this, and put it to his eyes, they were immediately opened. Thence did the fame spread; thence did Your praises burn—shine; thence was the mind of that enemy, though not yet enlarged to the wholeness of believing, restrained from the fury of persecuting. [Confessions IX.7, emphasis added]Speaking on Intercession of the Saints in Heaven:
Now he puts not his ear unto my mouth, but his spiritual mouth unto Your fountain, and drinks as much as he is able, wisdom according to his desire—happy without end. Nor do I believe that he is so inebriated with it as to forget me, seeing Thou, O Lord, whom he drinks, art mindful of us. [Confessions IX.3]
Surely, this was more than enough evidence that St Augustine not only was not a Protestant (teaching doctrines anathema to Protestant ears), but he was very much Catholic in his life and thought. And if the above wasn't enough, Dave Armstrong has put together his own list of "Augustine was Catholic, not Protestant" quotes, spanning even more subjects than these!
A special thank you to RdP at The Supplement - while I have read the Confessions before, I didn't notice many of these fine gems!