I wanted to make this thread as a resource to help Catholics show that our doctrine of indulgences is an ancient part of the faith.
I want to mention two things about my examples here. First, if you think about indulgences, you probably think of one of two things: either gaining an indulgence for yourself, or gaining one for a soul in purgatory. None of the examples in this article refer to the second thing. Perhaps I will make an article about that in the future.
Second, the first couple of examples may not appear to mention indulgences at first glance. I think they fit the definition of an indulgence upon close inspection. An indulgence remits the temporal punishment due to sin that has already been forgiven. An excommunication involves a temporal punishment of sin. In the passage from St. Paul, a man has been excommunicated, and St. Paul appears to remove his penance early, which makes this an indulgence.
In several other early examples of indulgences, Christians who have been convicted of sin are temporarily excommunicated as a penance, and they go to the prisons to see the Christians who have been imprisoned for their faith. They receive certificates from the imprisoned Christians recommending the Church to let the excommunicated Christians back into the fold early, which is a kind of indulgence.
Lastly, there are probably other early documents that can be cited in support of indulgences. Does anyone know of any?
The Doctrine of Indulgences in the Early Church Fathers
~57 A.D. - St. Paul - “For such a one this punishment by the majority is enough…you should rather turn to forgive and comfort him…I beg you to reaffirm your love for him. … What I have forgiven, if I have forgiven anything, has been for your sake in the presence of Christ.” (2 Corinthians 2:5-10)
~197 A.D. - Tertullian - “Some, not able to find this peace in the Church, have been used to seek it from the imprisoned martyrs. And so you [imprisoned Christians] ought to have it dwelling with you, and to cherish it, and to guard it, that you may be able perhaps to bestow it upon others.” (Ad Martyras Chapter 1)
222 A.D. - Tertullian - “[N]ow you are ascribing this power [of granting indulgences] even to your dear martyrs. As soon as someone of his own accord has taken on the fetters…at once the adulterers are swarming about…[and] prayers are humming in the air… Men and women crowd [them]…beg for [their] blessing…and return from there as [restored to] the community.” (On Modesty Chapter 22)
250 A.D. - St. Cyprian - “[A]ccording to your diligence…designate those by name to whom you desire that peace should be granted. For I hear that certificates [of indulgence] are [too freely] given.” (Letter 10 or 15 Paragraph 4)
And (250 A.D.): “[W]hen some of the lapsed…[demanded] the peace that had been promised to them by the martyrs and confessors…I wrote twice to the clergy…[that] if any who had received a certificate [of indulgence] from the martyrs were departing from this life, having made confession, and received the imposition of hands on them for repentance, they should be remitted to the Lord with the peace promised them by the martyrs.” (Letter 14 or 20 Paragraph 3)
314 A.D. - Council of Ancyra - “Concerning [various sinners]…a former decree excluded them [from the Church] until the hour of death, and to this some have assented. Nevertheless, being desirous to use somewhat greater lenity, we have ordained that they fulfil ten years [of penance], according to the prescribed degrees.” (Canon 21)
314 A.D. - Council of Arles - “Concerning those who carry letters from the confessors, be it resolved that, when they have handed over those letters, they receive other letters of reference.” (Canon 10 or 9)
379 A.D. - St. Basil - “We do not judge [a penance] altogether by the length of time, but by the circumstances of the penance.” (Canonical Epistle to Amphilochius Canon 84)
380 A.D. - St. Gregory of Nyssa - “[F]ornicators [should] be three years wholly ejected from prayer…and [after an additional six year period] admitted [back] to communion; but the [additional six years] may be lessened to them who of their own accord confess, and are earnest penitents.” (Canonical Epistle to Letojus Canon 4)
~650 A.D. - St. Cummian writes a book about penance in which he lists several ways a penance can be shortened. Among them, he notes that “twelve three-day periods” of penance can be “the equivalent of a year” of penance. He says that a penitent can shorten his penance if he spends “one hundred days with half a loaf and an allowance of dry bread and water and salt, [and] sing[s] fifty psalms during each night.” Or, the penitent can do “fifty special fasts, with one night intervening.” (Penitential Chapter VIII Canons 25-28)
~679 A.D. - St. Theodore of Tarsus - “Penitents according to the canons ought not to communicate before the conclusion of the penance; we, however, out of pity give permission after a year or six months.” (Penitential Chapter 12 Canon 4)
740 A.D. - St. Egbert of York - “For him who can comply with what the penitential prescribes, well and good; for him who cannot, we give counsel of God’s mercy. Instead of one day on bread and water let him sing fifty psalms on his knees or seventy psalms without genuflecting. But if he does not know the psalms and cannot fast, let him, instead of one year on bread and water, give twenty-six solidi in alms, fast till [3:00 pm] on one day of each week and till Vespers on another, and in the three Lents bestow in alms half of what he receives.” (Penitential Chapter 13 Canon 11)
807 A.D. - According to the Catholic Encyclopedia article on indulgences, an Irish Synod of this year said that the fast of the second day of the week may be “redeemed” by singing one psalter or by giving one denarius to a poor person. (Canon 24)