On Repentance by Tertullian
Chapter IX.--Concerning the Outward Manifestations by Which This Second Repentance is to Be Accompanied.
The narrower, then, the sphere of action of this second and only (remaining) repentance, the more laborious is its probation; in order that it may not be exhibited in the conscience alone, but may likewise be carried out in some (external) act. This act, which is more usually expressed and commonly spoken of under a Greek name, is exomologesis , whereby we confess our sins to the Lord, not indeed as if He were ignorant of them, but inasmuch as by confession satisfaction is settled, of confession repentance is born; by repentance God is appeased. And thus exomologesis is a discipline for man's prostration and humiliation, enjoining a demeanor calculated to move mercy. With regard also to the very dress and food, it commands (the penitent) to lie in sackcloth and ashes, to cover his body in mourning, to lay his spirit low in sorrows, to exchange for severe treatment the sins which he has committed; moreover, to know no food and drink but such as is plain, -- not for the stomach's sake, to wit, but the soul's; for the most part, however, to feed prayers on fastings, to groan, to weep and make outcries unto the Lord your God; to bow before the feet of the presbyters, and kneel to God's dear ones; to enjoin on all the brethren to be ambassadors to bear his deprecatory supplication (before God). All this exomologesis (does), that it may enhance repentance; may honour God by its fear of the (incurred) danger; may, by itself pronouncing against the sinner, stand in the stead of God's indignation, and by temporal mortification (I will not say frustrate, but) expunge eternal punishments. Therefore, while it abases the man, it raises him; while it covers him with squalor, it renders him more clean; while it accuses, it excuses; while it condemns, it absolves. The less quarter you give yourself, the more (believe me) will God give you.