When did the Roman Catholic idea of mortal sins develop? Also the theory of being in a “state of grace” and that mortal sins “drive out” the grace of God? I have seen many of the early Latin fathers talking about mortal sin, but I don’t see where they hold the theory of being in a state of grace (whatever that means). I have looked it up and can’t find a single thing on this “being in a state of grace” thing. When did this develop? Was it another medieval invention like purgatory and indulgences?
https://www.newadvent.org/cathen/14004b.htm Augustine. The answer is always Augustine. And if you're Catholic, go to newadvent.org and check the old Catholic Encyclopedia article on the subject. It's an excellent resource.
We do have a Non-Anglican Section, here: https://forums.anglican.net/forums/non-anglican-discussion.37/ Many fruitful threads there, and this is now among them. As for the Catholic Answers Forums, there was a big discussion about it here: https://forums.anglican.net/threads/catholic-answers-forums-shutting-down.4097/
Catholic Answers is, I believe, still going. It was the forum they closed. It was closed for the same reason as everything closes down: not enough money. They introduced a voluntary pay-for-membership option for the forum but they say too many members remained free members. They said they could no longer afford the expense of running the forum. I do believe there are other Roman Catholic fora.
Why did the idea of mortal sins develop? It developed because people are fallible and get thing wrong all the time. Proof of that is the writing by Irenaeus, Against Heresies, around 180 A.D. (latter 2nd Century). In less than 150 years after Christ's ascension, a wide variety of errors were being taught and popularized in some parts of the church. In an effort to emphasize the importance of holiness, it seems that some church leaders would exclude people from services if they were known to have committed a serious sin such as adultery, murder, etc. Those people, to merit a return to the church, would have to demonstrate their repentance by hanging around outside the building during the services, wailing and expressing sorrow (see the writings of Hippolytus of Rome), for many months. Perhaps this was one of the roots upon which the false idea eventually developed, the idea that some sins immediately result in loss of God's saving grace until one repents. Later on it became coupled with additional developments: auricular confession and the assignment of penances. In other words, these things sometimes start with the recognition of a problem (such as, when people assume they have liberty to willfully sin) and the subsequent overzealous steps taken in an effort to curb the problem (the better solution would have been to provide thorough, balanced teaching from the Bible to show that grace is not a license to sin). I'm not a historian, so I can't speak to exactly when and how this or that error developed. Much of the details may be lost to us anyway. But the important thing is to know the truth from the Bible and be able to recognize error when we see it.
The distinction is a biblical one: Some modern translations like the RSV and NRSV just use "mortal sin", while the NIV is closer to the KJV in this instance:
No, the passages referring to the "unforgivable sin" are in the Synoptic Gospels. Perhaps they are the same thing, or perhaps not. My only point is that the language of categorizing sin as to whether it's "mortal" or not is simply biblical usage. Whether the later Church interpreted it properly is another matter.
As Invictus said the idea of mortal and venial sin is rooted in 1 John 5:16-17. From Catholic Answers: The Didache “Watch for your life’s sake. Let not your lamps be quenched, nor your loins unloosed; but be ready, for you know not the hour in which our Lord comes. But you shall assemble together often, seeking the things which are befitting to your souls: for the whole time of your faith will not profit you, if you be not made complete in the last time” (Didache 16 [A.D. 70]). Hermas “And as many of them . . . as have repented, shall have their dwelling in the tower [i.e., the Church]. And those of them who have been slower in repenting shall dwell within the walls. And as many as do not repent at all, but abide in their deeds, shall utterly perish. . . . But if any one relapse into strife, he will be cast out of the tower, and will lose his life. Life is the possession of all who keep the commandments of the Lord” (The Shepherd 3:8:7 [A.D. 80]). Ignatius of Antioch “And pray without ceasing in behalf of other men; for there is hope of the repentance, that they may attain to God. For cannot he that falls arise again, and he may attain to God?” (Letter to the Ephesians 10 [A.D. 110]). Justin Martyr “[E]ternal fire was prepared for him who voluntarily departed from God and for all who, without repentance, persevere in apostasy” (fragment in Irenaeus, Against Heresies 5:26 [A.D. 156]). Irenaeus “[T]he ungodly and unrighteous and wicked and profane among men [shall go] into everlasting fire; but [God] may, in the exercise of his grace, confer immortality on the righteous, and holy, and those who have kept his commandments, and have persevered in his love, some from the beginning [of their Christian course], and others from [the date of] their penance, and may surround them with everlasting glory” (Against Heresies 1:10:1 [A.D. 189]). Tertullian “[Regarding confession, some] flee from this work as being an exposure of themselves, or they put it off from day to day. I presume they are more mindful of modesty than of salvation, like those who contract a disease in the more shameful parts of the body and shun making themselves known to the physicians; and thus they perish along with their own bashfulness” (Repentance 10:1 [A.D. 203]). “Discipline governs a man, power sets a seal upon him; apart from the fact that power is the Spirit, but the Spirit is God. What, moreover, used [the Spirit] to teach? That there must be no communicating with the works of darkness. Observe what he bids. Who, moreover, was able to forgive sins? This is his alone prerogative: for ‘who remits 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?” (Modesty 21 [A.D. 220]). Cyprian of Carthage “Of how much greater faith and salutary fear are they who . . . confess their sins to the priests of God in a straightforward manner and in sorrow, making an open declaration of conscience. . . . I beseech you, brethren, let everyone who has sinned confess his sin while he is still in this world, while his confession is still admissible, while the satisfaction and remission made through the priests are still pleasing before the Lord” (The Lapsed 28 [A.D. 251]). Pacian of Barcelona “Stinginess is remedied by generosity, insult by apology, perversity by honesty, and for whatever else, amends can be made by practice of the opposite. But what can he do who is contemptuous of God? What shall the murderer do? What remedy shall the fornicator find? . . . These are capital sins, brethren, these are mortal. Someone may say: ‘Are we then about to perish? . . . Are we to die in our sins?’ . . . I appeal first to you brethren who refuse penance for your acknowledged crimes. You, I say, who are timid after your impudence, who are bashful after your sins, who are not ashamed to sin but now are ashamed to confess” (Sermon Exhorting to Penance 4 [A.D. 385]). Jerome “There are venial sins and there are mortal sins. It is one thing to owe ten thousand talents, another to owe but a farthing. We shall have to give an accounting for an idle word no less than for adultery. But to be made to blush and to be tortured are not the same thing; not the same thing to grow red in the face and to be in agony for a long time. . . . If we entreat for lesser sins we are granted pardon, but for greater sins, it is difficult to obtain our request. There is a great difference between one sin and another” (Against Jovinian 2:30 [A.D. 393]). Augustine “[N]othing could have been devised more likely to instruct and benefit the pious reader of sacred Scripture than that, besides describing praiseworthy characters as examples, and blameworthy characters as warnings, it should also narrate cases where good men have gone back and fallen into evil, whether they are restored to the right path or continue irreclaimable; and also where bad men have changed, and have attained to goodness, whether they persevere in it or relapse into evil; in order that the righteous may be not lifted up in the pride of security, nor the wicked hardened in despair of cure” (Against Faustus 22:96 [A.D. 400]). “[A]lthough they were living well, [they] have not persevered therein; because they have of their own will been changed from a good to an evil life, and on that account are worthy of rebuke; and if rebuke should be of no avail to them, and they should persevere in their ruined life until death, they are also worthy of divine condemnation forever. Neither shall they excuse themselves, saying—as now they say, ‘Why are we rebuked?’—so then, ‘Why are we condemned, since indeed, that we might return from good to evil, we did not receive that perseverance by which we should abide in good?’ They shall by no means deliver themselves by this excuse from righteous condemnation” (Admonition and Grace 11 [A.D. 426]). “But those who do not belong to the number of the predestined . . . are judged most justly according to their deserts. For either they lie under sin which they contracted originally by their generation and go forth [from this life] with that hereditary debt which was not forgiven by regeneration [baptism], or [if it was forgiven by regeneration] they have added others besides through free choice: choice, I say, free; but not freed. . . . Or they receive God’s grace, but they are temporal and do not persevere; they abandon it and are abandoned. For by free will, since they have not received the gift of perseverance, they are sent away in God’s just and hidden judgment” (ibid., 13). Caesarius of Arles “Although the apostle [Paul] has mentioned many grievous sins, we, nevertheless, lest we seem to promote despair, will state briefly what they are. Sacrilege, murder, adultery, false witness, theft, robbery, pride, envy, avarice, and, if it is of long standing, anger, drunkenness, if it is persistent, and slander are reckoned in their number. Or if anyone knows that these sins dominate him, if he does not do penance worthily and for a long time, if such time is given him . . . he cannot be purged in that transitory fire of which the apostle spoke [1 Cor. 3:11–15], but the eternal flames will torture him without any remedy. But since the lesser sins are, of course, known to all, and it would take too long to mention them all, it will be necessary for us only to name some of them. . . . There is no doubt that these and similar deeds belong to the lesser sins which, as I said before, can scarcely be counted, and from which not only all Christian people, but even all the saints could not and cannot always be free. We do not, of course, believe that the soul is killed by these sins, but still they make it ugly by covering it as if with some kind of pustules and, as it were, with horrible scabs” (Sermons 179[104]:2 [A.D. 522]).