The context of that quote that this responder makes is as follows:
Chapter 14.-Why the Father Does Not Teach All that They May Come to Christ.
Why, then, does He not teach all that they may come to Christ, except because all whom He teaches, He teaches in mercy, while those whom He teaches not, in judgment He teaches not? Since, "On whom He will He has mercy, and whom He will He hardeneth."59 But He has mercy when He gives good things. He hardens when He recompenses what is deserved. Or if, as some would prefer to distinguish them, those words also are his to whom the apostle says, "Thou sayest then unto me," so that he may be regarded as having said, "Therefore hath He mercy on whom He will, and whom He will He hardeneth," as well as those which follow,-to wit, "What is it that is still complained of? for who resists His will?" does the apostle answer, "O man, what thou hast said is false?" No; but he says, "O man, who art thou that repliest against God? Doth the thing formed say to him that formed it, Why hast thou made me thus? Hath not the potter power over the clay of the same lump? "60 and what follows, which you very well know. And yet in a certain sense the Father teaches all men to come to His Son. For it was not in vain that it was written in the prophets, "And they shall all be teachable of God." 61 And when He too had premised this testimony, He added, "Every man, therefore, who has heard of the Father, and has learned, cometh to me." As, therefore, we speak justly when we say concerning any teacher of literature who is alone in a city, He teaches literature here to everybody,-not that all men learn, but that there is none who learns literature there who does not learn from him,-so we justly say, God teaches all men to come to Christ, not because all come, but because none comes in any other way. And why He does not teach all men the apostle explained, as far as he judged that it was to be explained, because, "willing to show His wrath, and to exhibit His power, He endured with much patience the vessels of wrath which were perfected for destruction; and that He might make known the riches of His glory on the vessels of mercy which He has prepared for glory."62 Hence it is that the "word of the cross is foolishness to them that perish; but unto them that are saved it is the power of God."63 God teaches all such to come to Christ, for He wills all such to be saved, and to come to the knowledge of the truth. And if He had willed to teach even those to whom the word of the cross is foolishness to come to Christ beyond all doubt these also would have come. For He neither deceives nor is deceived when He says, "Everyone that hath heard of the Father, and hath learned, cometh to me." Away, then, with the thought that any one cometh not, who has heard of the Father and has learned.
Chapter 16.-Why the Gift of Faith is Not Given to All.
Faith, then, as well in its beginning as in its completion, is God's gift; and let no one have any doubt whatever, unless he desires to resist the plainest sacred writings, that this gift is given to some, while to some it is not given. But why it is not given to all ought not to disturb the believer, who believes that from one all have gone into a condemnation, which undoubtedly is most righteous; so that even if none were delivered therefrom, there would be no just cause for finding fault with God. Whence it is plain that it is a great grace for many to be delivered, and to acknowledge in those that are not delivered what would be due to themselves; so that he that glorieth may glory not in his own merits, which he sees to be equalled in those that are condemned, but in the Lord. But why He delivers one rather than another,-" His judgments are unsearchable, and His ways past finding out."70 For it is better in this case for us to hear or to say, "O man, who art thou that repliest against God?"71 than to dare to speak as if we could know what He has chosen to be kept secret. Since, moreover, He could not will anything unrighteous.
The reader will note, St. Augustine is not making a declaritive statement here regarding Predestination, rather - as great a saint as he was/is - he seems a bit "confused" on this issue and rather than make a declaritive statement, he says: "His judgments are unsearchable, and His ways past finding out." So, for our Calvinist friends to attempt to latch on to this section of St. Augustine and attribute this as a proof-text of St. Augustine supporting some sort of Calvininstic belief in Predestination (which is an anachronistic argument to begin with) seems a bit disingenuous. It is also noted that from Chapter 14, above, St. Augustine is still placing the "blame" (so to speak) back on man - and the will of man - when he says:
This text cannot be stolen to aid the Calvinist's claims!