Using imagery from the Old Testament, Peter tells the scattered church that we are a priesthood. As priests we are a worshiping, mediating, exemplary collective. In other words, our purpose is first and foremost to worship God. But in lives of worship, we are also bring God near to others and bring them near to him while we live differently as an example of what God's kingdom ought to look like. This is not a individual call, but a corporate one - we do it together.