[T]he whole man, from the crown of the head to the sole of the foot, is so deluged, as it were, that no part remains exempt from sin, and, therefore, everything which proceeds from him is imputed as sin (Institutes of the Christian Religion, II, 1, 9).
We are all sinners by nature, therefore we are held under the yoke of sin. But if the whole man is subject to the dominion of sin, surely the will, which is its principal seat, must be bound with the closest chains (ibid., II, 2, 27).
[I]t is vain to look for anything good in our nature. I confess indeed, that all…iniquities do not break out in every individual. Still it cannot be denied that the hydra lurks in every breast. For as a body, while it contains and fosters the cause and matter of disease, cannot be called healthy, although pain is not actually felt; so a soul, while teeming with such seeds of vice, cannot be called sound. This similitude, however, does not apply throughout. In a body however morbid the functions of life are performed; but the soul, when plunged into that deadly abyss, not only labours under vice, but is altogether devoid of good (ibid., II, 3, 2).