Chapter 76 [LXIV.]—John of Constantinople.
He quotes also John, bishop of Constantinople, as saying “that sin is not a substance, but a wicked act.” Who denies this? “And because it is not natural, therefore the law was given against it, and because it proceeds from the liberty of our will.” Who, too, denies this? However, the present question concerns our human nature in its corrupted state; it is a further question also concerning that grace of God whereby our nature is healed by the great Physician, Christ, whose remedy it would not need if it were only whole. And yet your author defends it as capable of not sinning, as if it were sound, or as if its freedom of will were self-sufficient.
Reproduced in full. Translation: Nicene and Post-Nicene Fathers, series 1, vol. 5 (Schaff, 1887), public domain (Public domain).