And on the way he asked his disciples, "Who do people say that I am?" And they told him, "John the Baptist; and others say, Elijah; and others, one of the prophets." And he asked them, "But who do you say that I am?" Peter answered him, "You are the Christ." – Mark 8:27b-29 (ESV)
This is a turning point for Peter. He now articulates who Jesus truly is, the Christ, the expected, chosen one of God. This is also a huge step forward for the reader; while we have had this notion that Jesus was someone special, we now know that this IS the one we are to expect. There is no other. Our hope lies in Him and Him alone. This is the turning point for us all – the revelation of who exactly Jesus is.