Peter's confession in the Gospels marks the turning point in Jesus' ministry. In Mark and Matthew, the setting is Caesarea Philippi--the headwaters of the Jordan River, where a cave descends deep into the earth. On this site at the base of Mount Hermon, conquering foreign armies erected shrines to their pagan gods, claiming the land for their empires. For Jesus to ask, "Who do you say that I am?" in that setting poses a test to his followers, as the gift of life may involve the way of the cross.
After Peter's confessing Jesus to be the Christ in the Synoptics, Jesus warns that the Son of Man must suffer and die--to which his followers object. Before Peter's confessing Jesus as the Holy One of God in John, Jesus calls for ingesting the flesh and blood of the suffering Son of Man--at which even some of his disciples abandon him and walk with him no longer.
Whether the rock upon which the church stands is the legacy of Peter, the truth of his confession, or its revelatory origin, Jesus reminds us in Matthew 7 that the solid rock upon which to build is faithfully following Jesus. While the cost of discipleship may be dear, the gift of life is always worthy. In the words of the 19-year-old Quaker martyr, James Parnell, "Be willing that self shall suffer for truth, not the truth for self." Against such a foundational rock, the Gates of Hades will never prevail.
(Peter's Confession, Donald Jackson, Copyright 2002, The Saint John's Bible, Saint John's University, Collegeville, Minnesota USA. Used by permission. All rights reserved. Note this reflection on Peter's Confession by Michael Patella: http://www.saintjohnsbible.org/promotions/lp/itm/PDFs/PetersConfession.pdf.)