"I am not what I ought to be — ah, how imperfect and deficient! I am not what I wish to be — I abhor what is evil, and I would cleave to what is good! I am not what I hope to be — soon, soon shall I put off mortality, and with mortality all sin and imperfection. Yet, though I am not what I ought to be, nor what I wish to be, nor what I hope to be, I can truly say, I am not what I once was; a slave to sin and Satan; and I can heartily join with the apostle, and acknowledge, "By the grace of God I am what I am." John Newton as quoted in The Christian Pioneer (1856) edited by Joseph Foulkes Winks, p. 84
This is often paraphrased as "I am not the man I ought to be, I am not the man I wish to be, and I am not the man I hope to be, but by the grace of God, I am not the man I used to be."