As to those other things which we hold on the authority, not of Scripture, but of tradition, and which are observed throughout the whole world, it may be understood that they are held as approved and instituted either by the apostles themselves, or by plenary Councils, whose authority in the Church is most useful, . . .For often have I perceived, with extreme sorrow, many disquietudes caused to weak brethren by the contentious pertinacity or superstitious vacillation of some who, in matters of this kind, which do not admit of final decision by the authority of Holy Scripture, or by the tradition of the universal Church. (Letter to Januarius, 54, 1, 1; 54, 2, 3; cf. NPNF I, I:301)I believe that this practice [of not rebaptizing heretics and schismatics] comes from apostolic tradition, just as so many other practices not found in their writings nor in the councils of their successors, but which, because they are kept by the whole Church everywhere, are believed to have been commanded and handed down by the Apostles themselves. (On Baptism, 2, 7, 12; from William A. Jurgens, editor and translator, The Faith of the Early Fathers, 3 volumes, Collegeville, Minnesota: Liturgical Press, 1970, vol. 3: 66; cf. NPNF I, IV:430)
. . . the custom, which is opposed to Cyprian, may be supposed to have had its origin in apostolic tradition, just as there are many things which are observed by the whole Church, and therefore are fairly held to have been enjoined by the apostles, which yet are not mentioned in their writings. (On Baptism, 5,23:31, in NPNF I, IV:475)
The Christians of Carthage have an excellent name for the sacraments, when they say that baptism is nothing else than “salvation” and the sacrament of the body of Christ nothing else than “life.” Whence, however, was this derived, but from that primitive, as I suppose, and apostolic tradition, by which the Churches of Christ maintain it to be an inherent principle, that without baptism and partaking of the supper of the Lord it is impossible for any man to attain either to the kingdom of God or to salvation and everlasting life? (On Forgiveness of Sins and Baptism, 1:34, in NPNF I, V:28)
[F]rom whatever source it was handed down to the Church – although the authority of the canonical Scriptures cannot be brought forward as speaking expressly in its support. (Letter to Evodius of Uzalis, Epistle 164:6, in NPNF I, I:516)
The custom of Mother Church in baptizing infants [is] certainly not to be scorned, nor is it to be regarded in any way as superfluous, nor is it to be believed that its tradition is anything except Apostolic. (The Literal Interpretation of Genesis, 10,23:39, in William A. Jurgens, editor and translator, The Faith of the Early Fathers, 3 volumes, Collegeville, Minnesota: Liturgical Press, 1970, vol. 3: 86)
God has placed this authority first of all in his Church. (Explanations of the Psalms, Tract 103:8, PL 37:520-521, in Yves Congar, Tradition and Traditions: An Historical and Theological Essay, New York: Macmillan, 1967, 392)
But those reasons which I have here given, I have either gathered from the authority of the church, according to the tradition of our forefathers, or from the testimony of the divine Scriptures, or from the nature itself of numbers, and of similitudes. No sober person will decide against reason, no Christian against the Scriptures, no peaceable person against the church. (On the Trinity, 4,6:10; NPNF I, III:75)
It is obvious; the faith allows it; the Catholic Church approves; it is true. (Sermon 117, 6)
Will you, then, so love your error, into which you have fallen through adolescent overconfidence and human weakness, that you will separate yourself from these leaders of Catholic unity and truth, from so many different parts of the world who are in agreement among themselves on so important a question, one in which the essence of the Christian religion involved . . . ? (Against Julian I:7,34; in Robert B. Eno, Teaching Authority in the Early Church, Wilmington: Michael Glazier, 1984, 136)
And thus a man who is resting upon faith, hope, and love, and who keeps a firm hold upon these, does not need the Scriptures except for the purpose of instructing others. Accordingly, many live without copies of the Scriptures, even in solitude, on the strength of these three graces. (On Christian Doctrine, I, 39:43, in NPNF I, II:534)
And if any one seek for divine authority in this matter, though what is held by the whole Church, and that not as instituted by Councils, but as a matter of invariable custom, is rightly held to have been handed down by apostolical authority, still we can form a true conjecture of the value of the sacrament of baptism in the case of infants. (On Baptism, 4, 24, 32; NPNF I, IV:461)
It is not to be doubted that the dead are aided by prayers of the holy church, and by the salutary sacrifice, and by the alms, which are offered for their spirits . . . For this, which has been handed down by the Fathers, the universal church observes. (Sermon 172, in Joseph Berington and John Kirk, The Faith of Catholics, three volumes, London: Dolman, 1846; I: 439)
To be sure, although on this matter, we cannot quote a clear example taken from the canonical Scriptures, at any rate, on this question, we are following the true thought of Scriptures when we observe what has appeared good to the universal Church which the authority of these same Scriptures recommends to you; thus, since Holy Scripture cannot be mistaken, anyone fearing to be misled by the obscurity of this question has only to consult on this same subject this very Church which the Holy Scriptures point out without ambiguity. (Against Cresconius I:33; in Robert B. Eno, Teaching Authority in the Early Church, Wilmington: Michael Glazier, 1984, 134)
[L]et the reader consult the rule of faith which he has gathered from the plainer passages of Scripture, and from the authority of the Church . . . (On Christian Doctrine, 3,2:2, NPNF I, II:557)
Which just shows that Augustine was inconsistent.
So much for ‘unanimous consent.’
It might be!!
• Augustine, sermon:
"Christ, you see, built his Church not on a man but on Peter's confession. What is Peter's confession? 'You are the Christ, the Son of the living God.' There's the rock for you, there's the foundation, there's where the Church has been built, which the gates of the underworld cannot conquer. — John Rotelle, O.S.A., Ed., The Works of Saint Augustine , © 1993 New City Press, Sermons, Vol III/6, Sermon 229P.1, p. 327
Augustine, sermon:
Upon this rock, said the Lord, I will build my Church. Upon this confession, upon this that you said, 'You are the Christ, the Son of the living God,' I will build my Church, and the gates of hell shall not conquer her (Mt. 16:18). — John Rotelle, Ed., The Works of Saint Augustine (New Rochelle: New City, 1993) Sermons, Volume III/7, Sermon 236A.3, p. 48.
• Augustine, sermon:
For petra (rock) is not derived from Peter, but Peter from petra; just as Christ is not called so from the Christian, but the Christian from Christ. For on this very account the Lord said, 'On this rock will I build my Church,' because Peter had said, 'Thou art the Christ, the Son of the living God.' On this rock, therefore, He said, which thou hast confessed, I will build my Church. For the Rock (Petra) was Christ; and on this foundation was Peter himself built. For other foundation can no man lay than that is laid, which is Christ Jesus. The Church, therefore, which is founded in Christ received from Him the keys of the kingdom of heaven in the person of Peter, that is to say, the power of binding and loosing sins. For what the Church is essentially in Christ, such representatively is Peter in the rock (petra); and in this representation Christ is to be understood as the Rock, Peter as the Church. — Augustine Tractate CXXIV; Philip Schaff, Nicene and Post-Nicene Fathers: First Series, Volume VII Tractate CXXIV (http://www.ccel.org/ccel/schaff/npnf107.iii.cxxv.html)
• Augustine, sermon:
And Peter, one speaking for the rest of them, one for all, said, You are the Christ, the Son of the living God (Mt 16:15-16)...And I tell you: you are Peter; because I am the rock, you are Rocky, Peter-I mean, rock doesn't come from Rocky, but Rocky from rock, just as Christ doesn't come from Christian, but Christian from Christ; and upon this rock I will build my Church (Mt 16:17-18); not upon Peter, or Rocky, which is what you are, but upon the rock which you have confessed. I will build my Church though; I will build you, because in this answer of yours you represent the Church. — John Rotelle, O.S.A. Ed., The Works of Saint Augustine (New Rochelle: New City Press, 1993), Sermons, Volume III/7, Sermon 270.2, p. 289
• Augustine, sermon:
Peter had already said to him, 'You are the Christ, the Son of the living God.' He had already heard, 'Blessed are you, Simon Bar-Jona, because flesh and blood did not reveal it to you, but my Father who is in heaven. And I tell you, that you are Peter, and upon this rock I will build my Church, and the gates of the underworld shall not conquer her' (Mt 16:16-18)...Christ himself was the rock, while Peter, Rocky, was only named from the rock. That's why the rock rose again, to make Peter solid and strong; because Peter would have perished, if the rock hadn't lived. — John Rotelle, Ed., The Works of Saint Augustine (New Rochelle: New City, 1993) Sermons, Volume III/7, Sermon 244.1, p. 95
• Augustine, sermon:
...because on this rock, he said, I will build my Church, and the gates of the underworld shall not overcome it (Mt. 16:18). Now the rock was Christ (1 Cor. 10:4). Was it Paul that was crucified for you? Hold on to these texts, love these texts, repeat them in a fraternal and peaceful manner. — John Rotelle, Ed., The Works of Saint Augustine (New Rochelle: New City Press, 1995), Sermons, Volume III/10, Sermon 358.5, p. 193
• Augustine, Psalm LXI:
Let us call to mind the Gospel: 'Upon this Rock I will build My Church.' Therefore She crieth from the ends of the earth, whom He hath willed to build upon a Rock. But in order that the Church might be builded upon the Rock, who was made the Rock? Hear Paul saying: 'But the Rock was Christ.' On Him therefore builded we have been. — Philip Schaff, Nicene and Post-Nicene Fathers (Grand Rapids: Eerdmans, 1956), Volume VIII, Saint Augustin, Exposition on the Book of Psalms, Psalm LXI.3, p. 249. (http://www.ccel.org/ccel/schaff/npnf108.ii.LXI.html)
• Augustine, in “Retractions,”
In a passage in this book, I said about the Apostle Peter: 'On him as on a rock the Church was built.'...But I know that very frequently at a later time, I so explained what the Lord said: 'Thou art Peter, and upon this rock I will build my Church,' that it be understood as built upon Him whom Peter confessed saying: 'Thou art the Christ, the Son of the living God,' and so Peter, called after this rock, represented the person of the Church which is built upon this rock, and has received 'the keys of the kingdom of heaven.' For, 'Thou art Peter' and not 'Thou art the rock' was said to him. But 'the rock was Christ,' in confessing whom, as also the whole Church confesses, Simon was called Peter. But let the reader decide which of these two opinions is the more probable. — The Fathers of the Church (Washington D.C., Catholic University, 1968), Saint Augustine, The Retractations Chapter 20.1:.