The confession of sin during the whole course of the present life is exceedingly proper, for various reasons; and in the first place, because sin is an unspeakable evil. We suppose that those, who have experienced a perfected state of faith and love, will understand this remark more fully than others. They have tasted the bitter fruits of sin; they have in many cases endured a severe and terrible contest in driving it from the heart; they are now engaged momentarily in a constant warfare to prevent its re-entrance; they know it is the one great thing and the only thing which separates the soul from God; they know that every sin, even the smallest, is exceedingly heinous in God's sight; they feel that they had rather die a thousand deaths, than voluntarily commit even the smallest sin. Now when they remember, that during a considerable portion of their lives they were sinning against God every day and hour; despising, injuring, and insulting continually that great and good Being, whom now their hearts as continually adore, they are penetrated with the deepest grief. They never, never can forget the greatness of their former degradation and guilt. And, in their present state of mind, they never can remember it, without being, at each distinct retrospection, deeply humbled and penitent. Indeed, as true confession consists much more in the state of the heart than in the expression of the lips, and as the surest mark of true confession is an earnest striving after the opposite of that which is confessed as wrong, those, who are earnestly seeking and practicing holiness, may be said in the highest sense of the terms to be always acknowledging and always lamenting their sin. Their watching, their strife, their warfare is against sin, as the evil and bitter thing which their soul hates; and which their souls shall ever hate whenever and wherever committed, whether by themselves or others, at the present time or in times past.
— edited from The Interior or Hidden Life (2nd edition, 1844) Part 2, Chapter 16.