If, because the Lord said to Peter, “Upon this rock I will build My Church [Matt. 16:18].… To Thee I have given the keys of the kingdom of heaven,” or “Whatsoever thou shalt bind or loose on earth, shall be bound or loosed in heaven,” you therefore presume that the power of binding and loosing has descended to you, that is, to every church akin to Peter; what sort of man, then, are you, subverting and wholly changing the manifest intention of the Lord, who conferred the gift personally upon Peter? “On Thee,” He says, “I will build my Church,” and “I will give thee the keys,” not to the Church; and “whatsoever thou shalt have loosed or bound,” not what they shall have loosed or bound. For so the result actually teaches. In him (Peter) the Church was reared, that is, through him (Peter) himself; he himself tried the key; you see what key: “Men of Israel, let what I say sink into your ears; Jesus, the Nazarene, a man appointed of God for you,”[65] and so forth. Peter himself, therefore, was the first to unbar, in Christ's baptism, the entrance to the kingdom of heaven, in which are loosed the sins that aforetime were bound.…
What, now, has this to do with the Church and your Church, indeed, O Psychic? For in accordance with the person of Peter, it is to spiritual men that this power will correspondingly belong, either to an Apostle or else to a prophet.… And accordingly the “Church,” it is true, will forgive sins; but it will be the Church of the Spirit, by a spiritual man; not the Church which consists of a number of bishops.
Ch. 22. But you go so far as to lavish this power upon martyrs indeed; so that no sooner has any one, acting on a preconceived arrangement, put on soft bonds in the nominal custody now in vogue, than adulterers beset him, fornicators gain access to him; instantly prayers resound about him; instantly pools of tears of the polluted surround him; nor are there any who are more diligent in purchasing entrance to the prison than they who have lost the fellowship of the Church.… Whatever authority, whatever reason, restores ecclesiastical peace to the adulterer and the fornicator, the same will be bound to come to the aid of the murderer and the idolater in their repentance.
(e) Tertullian, Ad Martyres, 1. (MSL, 1:693.)
The following extract from Tertullian's little work addressed to martyrs in prison, written about 197, shows that in his earlier life as a Catholic Christian he did not disapprove of the practice of giving libelli pacis by the confessors, a custom which in his more rigoristic period under the influence of Montanism he denounced most vehemently; see preceding extract from De Pudicitia, ch. 22. The reference to some discord among the martyrs is not elsewhere explained. For libelli pacis, see Cyprian, Ep. 10 (=Ep. 15), 22 (=21).
O blessed ones, grieve not the Holy Spirit, who has entered with you into the prison; for if He had not gone with you there, you would not be there to-day. Therefore endeavor to cause Him to remain with you there; so that He may lead you thence to the Lord. The prison, truly, is the devil's house as well, wherein he keeps his family.… Let him not be successful in his own kingdom by setting you at variance with one another, but let him find you armed and [pg 188] fortified with concord; for your peace is war with him. Some, not able to find peace in the Church, have been accustomed to seek it from the imprisoned martyrs. Therefore you ought to have it dwelling with you, and to cherish it and guard it, that you may be able, perchance, to bestow it upon others.
(f) Tertullian, De Pudicitia, 19. (MSL, 2:1073.)
The distinction between mortal and venial sins became of great importance in the administration of penance and remained as a feature of ecclesiastical discipline from the time of Tertullian. The origin of the distinction was still earlier. See above, an extract from the same work.