Our Father, Who Art In Heaven

As Jesus instructs His disciples to pray, He's very intentional with the way it starts out: "Our Father, who art in heaven." What does it mean that God is our Father? Old Testament passages have plenty of evidence that God is like a father, but what exactly does it mean to the Christian that God is our 'Heavenly Father?' Jac Munson talks about the privilege that we've been given to call God 'Father' because of the sonship in which Jesus gave up so that we could become sons of God.