Before His suffering the Lord Jesus Christ, as you know, chose His disciples, who He called Apostles. Among these Apostles almost everywhere Peter alone merited to represent the whole Church. For the sake of his representing the whole Church, which he alone could do, he merited to hear: "I will give you the keys of the kingdom of Heaven." For it was not one man, but the unity of the Church, which received those keys. In that way, therefore, Peter's own excellence is foretold, because he acted the part of the unity and totality of the Church herself, when to him it was said, "I hand over to you," what was in fact handed over to all.
This quote from St. Augustine seems to contradict another important quote on the keys of the kingdom of Heaven from Tertullian's treatise on Modesty, again from Jurgens :
I now inquire into your opinion, to see whence you usurp this right for the Church. Do you presume, because the Lord said to Peter, 'On this rock I will build my Church, I have given you the keys of the kingdom of heaven,' or 'whatever you shall have bound or loosed on earth will be bound of loosed in heaven,' that the power of binding and loosing has thereby been handed on to you, that is, to every Church akin to Peter? What kind of man are you, subverting and changing what was the manifest intent of the Lord when He conferred this personally upon Peter? On you, He says, I will build my Church; and I will give 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.
Although this quote is from Tertullian's Montanist period, the above quote is accepted as orthodox because it has no content relating to the Montanist Heresy.
St. Augustine and Tertullian seem to be saying different things. How is it then that the quote from St. Augustine and the quote from Tertullian can both be considered orthodox? They can both be considered orthodox because they are saying the same thing from opposite perspectives.
Tertullian makes it very clear that it was to Peter personally and not the Church to whom Christ gave the keys. Not only that, he also says that the power of binding and loosing has been given solely to Peter, even though Scripture clearly states that Christ is speaking to all the Apostles in Matthew 18:18.
Doesn't Tertullian ignore the other Apostles in 18:18? No. The only way to understand him is by realising that the other Apostles only have the power of binding and loosing when they are in union with Peter. That is, Christ gives the power of binding and loosing to the Church, which, as St. Augustine says, "Peter alone merited to represent." As St. Ambrose of Milan said in his Commentaries on Twelve of David's Psalms, "Where Peter is, there is the Church."
With this understanding we can see how St. Augustine can say that the keys were given to all without denying that the keys were given solely to Peter. Peter is all. That is, Peter is "the unity and totality of the Church herself."