CCC 392 Scripture speaks of a sin of these angels.269 This "fall" consists in the free choice of these created spirits, who radically and irrevocably rejected God and his reign. We find a reflection of that rebellion in the tempter's words to our first parents: "You will be like God."270 The devil "has sinned from the beginning"; he is "a liar and the father of lies".271
CCC 393 It is the irrevocable character of their choice, and not a defect in the infinite divine mercy, that makes the angels' sin unforgivable. "There is no repentance for the angels after their fall, just as there is no repentance for men after death."272
et factum est proelium in caelo Michahel et angeli eius proeliabantur cum dracone et draco pugnabat et angeli eius et non valuerunt neque locus inventus est eorum amplius in caelo et proiectus est draco ille magnus serpens antiquus qui vocatur Diabolus et Satanas qui seducit universum orbem proiectus est in terram et angeli eius cum illo missi sunt et audivi vocem magnam in caelo dicentem nunc facta est salus et virtus et regnum Dei nostri et potestas Christi eius quia proiectus est accusator fratrum nostrorum qui accusabat illos ante conspectum Dei nostri die ac nocte et ipsi vicerunt illum propter sanguinem agni et propter verbum testimonii sui et non dilexerunt animam suam usque ad mortem propterea laetamini caeli et qui habitatis in eis vae terrae et mari quia descendit diabolus ad vos habens iram magnam sciens quod modicum tempus habet
And there was a great battle in heaven, Michael and his angels fought with the dragon, and the dragon fought and his angels: And they prevailed not, neither was their place found any more in heaven. And that great dragon was cast out, that old serpent, who is called the devil and Satan, who seduceth the whole world; and he was cast unto the earth, and his angels were thrown down with him. And I heard a loud voice in heaven, saying: Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: because the accuser of our brethren is cast forth, who accused them before our God day and night. And they overcame him by the blood of the Lamb, and by the word of the testimony, and they loved not their lives unto death. Therefore rejoice, O heavens, and you that dwell therein. Woe to the earth, and to the sea, because the devil is come down unto you, having great wrath, knowing that he hath but a short time.—The Apocalypse of St. John 12:7-12.
In her diary, Divine Mercy in My Soul, Saint Faustina Kowalska recorded that she received a private revelation regarding intercessory prayer from Jesus who told her to “Call upon My mercy on behalf of sinners; I desire their salvation. When you say this prayer, with a contrite heart and with faith on behalf of some sinner, I will give them the grace of conversion. This is the prayer:
O Blood and Water, which gushed forth from the Heart of Jesus as a fount of Mercy for us, I trust in You (Diary, 186-187).—Judy Keane, Catholic Exchange.
Today I was led by an Angel to the chasms of hell. It is a place of great torture; how awesomely large and extensive it is! The kinds of tortures I saw: the first torture that constitutes hell is the loss of God; the second is perpetual remorse of conscience; the third is that one’s condition will never change; the fourth is the fire that will penetrate the soul without destroying it – a terrible suffering, since it is a purely spiritual fire, lit by God’s anger; the fifth torture is continual darkness and a terrible suffocating smell, and, despite the darkness, the devils and the souls of the damned see each other and all the evil, both of others and their own; the sixth torture is the constant company of Satan; the seventh torture is horrible despair, hatred of God, vile words, curses and blasphemies.—St. Maria Faustyna Kowalska, Diary 741.