Are we ourselves people of God? Have we been born again? Have we the MARKS which always accompany the new birth–sense of sin, faith in Jesus, love of others, righteous living, separation from the world? Let us never be content until we can give a satisfactory answer to these questions.
~ J.C. Ryle
Expository Thoughts on the Gospels: John, volume 1, [Carlisle, PA: Banner of Truth, 1987], 17.