The necessity of repentance may seem at first sight a very simple and elementary truth. And yet volumes might be written to show the fullness of the doctrine, and the suitableness of it to every age and time, and to every rank and class of mankind. It is inseparably connected with right views of God, of human nature, of sin, of Christ, of holiness, and of heaven.
All have sinned and come short of the glory of God. All need to be brought to a sense of their sins–to a sorrow for them–to a willingness to give them up–and to a hunger and thirst after pardon. All, in a word, need to be born again and to flee to Christ. This is repentance unto life. Nothing less than this is required for the salvation of any man.
~ J.C. Ryle
Expository Thoughts on the Gospels: Mark, [Carlisle, PA: Banner of Truth, 1985], 115.