Sin says, ‘I’m not sin at all.’ Then Sin says, ‘I’m pleasant. ‘Yes, pleasant poison. Then Sin says, ‘Ah! do you call that sin? Well it is but a little sin.’ Alas! alas! for us men there can be no little sin, unless there be a little God against whom to commit it. Then Sin says, ‘It is a common good; good people do that.’ A good man has crooked legs; are crooked legs therefore no evil? He has stiff joints; are stiff joints therefore no evil? Ah! men don’t argue that way about the natural evil, but they do about the spiritual evil, because they love sin, and will take any excuse for it, and never readier than when they find it in a good man.
– Moody Stuart, The Life of John Duncan, p. 109.