Primacy of St. Peter:
Clement of Alexandria
“[T]he blessed Peter, the chosen, the pre-eminent, the first among the disciples, for whom alone with himself the Savior paid the tribute [Matt. 17:27], quickly grasped and understood their meaning. And what does he say? `Behold, we have left all and have followed you’” [Matt. 19:27; Mark 10:28] (Who Is the Rich Man That is Saved? 21:3-5 [A.D. 200]).
Tertullian
“For though you think that heaven is still shut up, remember that the Lord left the keys of it to Peter here, and through him to the Church, which keys everyone will carry with him if he has been questioned and made a confession [of faith]” (Antidote Against the Scorpion 10 [A.D. 211]).
Tertullian
“[T]he Lord said to Peter, ‘On this rock I will build my Church, I have given you the keys of the kingdom of heaven [and] whatever you shall have bound or loosed on earth will be bound or loosed in heaven’ [Matt. 16:18-19] . . . Upon you, he says, I will build my Church; and I will give to you the keys, not to the Church; and whatever you shall have bound or you shall have loosed, not what they shall have bound or they shall have loosed” (Modesty 21:9-10 [A.D. 220]).
The Letter of Clement to James
“Be it known to you, my lord, that Simon [Peter], who, for the sake of the true faith, and the most sure foundation of his doctrine, was set apart to be the foundation of the Church, and for this end was by Jesus Himself, with His truthful mouth, named Peter, the first-fruits of our Lord, the first of the apostles; to whom first the Father revealed the Son; whom the Christ, with good reason, blessed; the called, and elect” (Letter of Clement to James 2 [A.D. 221])
Origin
"f we were to attend carefully to the gospels, we should also find, in relation to those things which seem to be common to Peter . . . a great difference and a preeminence in the things [Jesus] said to Peter, compared with the second class [of apostles]. For it is no small difference that Peter received the keys not of one heaven but of more, and in order that whatsoever things he binds on earth may be bound not in one heaven but in them all, as compared with the many who bind on earth and loose on earth, so that these things are bound and loosed not in [all] the heavens, as in the case of Peter, but in one only; for they do not reach so high a stage with power as Peter to bind and loose in all the heavens" (Commentary on Matthew 13:31 [A.D. 248]).