Some of the principles articulated by John Calvin remain at the core of Presbyterian beliefs.  Among these are the sovereignty of God, the authority of scripture, justification by grace through faith and the priesthood of all believers.  What they mean is that God is the supreme authority throughout the universe.  Our knowledge of God and God's purpose for humanity comes from the Bible, particularly what is revealed in the New Testament through the life of Jesus Christ.  Our salvation (justification) through Jesus is God's generous gift to us and not the result of our own accomplishments.  It is everyone's job - ministers and lay people alike - to share this Good News with the whole world.