There are many different metaphors that the Bible uses to describe Jesus. In this passage, Peter says that Jesus is a living stone (jewell), that is chosen and precious, and that God has appointed to be the cornerstone of the true temple. The true temple are those who are born again. Now we are also living stones, precious and valued in the sight of God. Jesus is the rock on which every human being will build their life upon through faith, or will find their life broken upon by not believing.