Discipline governs a man, power sets a seal upon him; apart from the fact that power is the Spirit, but the Spirit is God. .. Who was able to forgive sins? This is His alone prerogative: for “who remitteth sins but God alone?” and, of course, (who but He can remit) mortal sins, such as have been committed against Himself, and against His temple? For, as far as you are concerned, such as are chargeable with offence against you personally, you are commanded, in the person of Peter, to forgive even seventy times sevenfold. And so, if it were agreed that even the blessed apostles had granted any such indulgence (to any crime) the pardon of which (comes) from God, not from man, it would be competent (for them) to have done so, not in the exercise of discipline, but of power. For they both raised the dead, which God alone (can do), and restored the debilitated to their integrity, which none but Christ (can do); nay, they inflicted plagues too, which Christ would not do. For it did not beseem Him to be severe who had come to suffer. Smitten were both Ananias and Elymas —Ananias with death, Elymas with blindness—in order that by this very fact it might be proved that Christ had had the power of doing even such (miracles). So, too, had the prophets (of old) granted to the repentant the pardon of murder, and therewith of adultery, inasmuch as they gave, at the same time, manifest proofs of severity. Exhibit therefore even now to me, apostolic sir, prophetic evidences, that I may recognise your divine virtue, and vindicate to yourself the power of remitting such sins! If, however, you have had the functions of discipline alone allotted you, and (the duty) of presiding not imperially, but ministerially; who or how great are you, that you should grant indulgence, who, by exhibiting neither the prophetic nor the apostolic character, lack that virtue whose property it is to indulge?
–On Modesty XXI
I have, even now, a test whereby to prove (the presence of) Christ (in you). If Christ is in the martyr for this reason, that the martyr may absolve adulterers and fornicators, let Him tell publicly the secrets of the heart, that He may thus concede (pardon to) sins; and He is Christ. For thus it was that the Lord Jesus Christ showed His power: “Why think ye evil in your hearts? For which is easier, to say to the paralytic, Thy sins are remitted thee; or, Rise and walk? Therefore, that ye may know the Son of man to have the power upon earth of remitting sins, I say to thee, paralytic, Rise, and walk.” If the Lord set so much store by the proof of His power as to reveal thoughts, and so impart health by His command, lest He should not be believed to have the power of remitting sins; it is not lawful for me to believe the same power (to reside) in any one, whoever he be, without the same proofs.
— On Modesty XXII