¹⁷ Jesus replied, “Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. ¹⁸ And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. ¹⁹ I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” (Matthew 16:17-19, NIV)

Some thoughts from N.T. Wright:

Jesus isn’t going to build an actual city, or an actual Temple. He is going to build a community, consisting of all those who give allegiance to him as God’s anointed king. And this movement, this community, starts then and there, at Caesarea Philippi, with Peter’s declaration.

Wright, T. (2004). Matthew for Everyone, Part 2: Chapters 16-28 (p. 8). London: Society for Promoting Christian Knowledge.

And from Stanley Hauerwas:

Peter has been given the office of unity, established through time and across space, to provide the church with the means for us to contend with one another so that the gates of hades will not prevail against us. Peter was not called to “keep the peace,” but rather to insure that the church has the conflicts necessary for its holiness. Without the existence of such a church there will be no salvation.

Hauerwas, S. (2006). Matthew (p. 151). Grand Rapids, MI: Brazos Press.