The Marks of the New Birth

How is every one that is 'born of the Spirit,'-that is, born again,-born of God? What is meant by the being born again, the being born of God, or being born of the Spirit? What is implied in the being a son or a child of God, or having the Spirit of adoption? That these privileges, by the free mercy of God, are ordinarily annexed to baptism (which is thence termed by our Lord in a preceding verse, the being 'born of water and of the Spirit') we know; but we would know what these privileges are: What is the new birth?