John Newton in a letter to his friend William Cowper
"I am willing to hope that you will be made a messenger of light and peace to his soul. The Lord's hand is not shortened that he cannot save. He can do great things in a small time, as you know from your own experience. In a moment, in the twinkling of an eye, he can command light to shine out of darkness. If he speaks, it is done... One glimpse of the worth of the soul, the evil of sin, and the importance of eternity, will effect that which hath been in vain attempted by repeated arguments."
[Cowper's brother, John, converted on his deathbed a few days later]