Newman on sin and habit
From a discourse titled “Neglect of Divine Calls and Warnings”:
[E]very sin has a history: it is not an accident; it is the fruit of former sins in thought or deed; it is the token of a habit deeply seated and widely spread; it is the aggravation of a virulent disease; and, as the last straw is said to break the horse’s back, so our last sin, whatever it is, is that which destroys our hope, and forfeits our place in heaven…. And that last sin need not be a great sin, need not be greater than those which have gone before it; perhaps it may be less. There was a rich man, mentioned by our Lord, who, when his crops were plentiful, said within himself, “What shall I do, for I have not where to bestow my fruits? I will pull down my barns, and build greater; and I will say to my soul, Soul, thou hast much goods laid up for many years; take thy rest, eat, drink, make good cheer.” He was carried off that very night. This was not a very striking sin, and surely it was not his first great sin; it was the last instance of a long course of acts of self-suffiency and forgetfulness of God, not greater in intensity than any before it, but completing their number.