Jonah 3:8

Recall that Daniel, passionate man though he was, spent many days fasting. He received as recompense an awesome vision so that he tamed the fury of the lions and turned them into the mildest of sheep, not by changing their nature but by diverting their purpose without loss of their ferocity. The Ninevites too made use of the remedy of fasting and won from the Lord a reprieve. Animals as well as human beings were included in the fast, so that all living things would abstain from evil practices. This total response won the favor of the Lord of all.

"For word came unto the king of Nineveh, and he arose from his throne, and he laid his robe from him, and covered him with sackcloth, and sat in ashes. And he caused it to be proclaimed and published through Nineveh by the decree of the king and his nobles, saying, Let neither man nor beast, herd nor flock, taste any thing: let them not feed, nor drink water: But let man and beast be covered with sackcloth, and cry mightily unto God: yea, let them turn every one from his evil way, and from the violence that is in their hands. Who can tell if God will turn and repent, and turn away from his fierce anger, that we perish not?" LXX: 'the message reached the king of Nineveh, and he arose from his throne, took off his robe and covered himself with sackcloth, and he sat down upon the earth. And by the order of the king and his nobles it was announced throughout Nineveh, saying, it is forbidden for any man or beast or oxen or sheep to eat anything, to drink any water. Men and beasts were covered in sackcloth and cried out to the Lord mightily. Let each one turn away from his wicked practises and from the unfairness that was in his hands, saying, who knows if God will turn and repent, if he will not abandon the fierceness of his wrath so that we might not die?'. I know certain men for whom the king of Nineveh, (who is the last to hear the proclamation and who descends from his throne, and forgoes the ornaments of his former vices and dressed in sackcloth sits on the ground, he is not content with his own conversion, preaches penitence to others with his leaders, saying, "let the men and beasts, big and small of size, be tortured by hunger, let them put on sackcloth, condemn their former sins and betake themselves without reservation to penitence!) is the symbol of the devil, who at the end of the world, (because no spiritual creature that is made reasoning by God will perish), will descend from his pride and do penitence and will be restored to his former position. To support this opinion they use this example of Daniel in which Nebuchadnezzar after seven years of penitence is returned to his former reign. [Dan. 4:24, 29, 33] But because this idea is not in the Holy Scripture and since it completely destroys the fear of God, (for men will slide easily into vices if they believe that even the devil, the creator of wickedness and the source of all sins, can be saved if he does penitence), we must eradicate this from our spirits. Let us remember though that the sinners in the Gospel are sent to the eternal fire [Mt. 25:41], which is prepared for the devil and his angels, about whom is said, "their worm will not die and their fire will not be extinguished" [Is. 66:24]. All the same we know that God is mild, and we sinners do not enjoy his cruelty, but we read, "the Lord is kindly and righteous, and our God will be merciful" [Ps. 114:5]. The justice of God is surrounded by mercy, and it is by this route that he proceeds to judgement: he spares to judge, he judges to be merciful. "Mercy and Truth are to be found in our path; Justice and Peace are to be embraced" [Ps. 84:11]. Moreover if all spiritual creatures are equal and if they raise themselves up by their virtues to heaven, or by their vices take themselves to the depths, then after a long circuit and infinite centuries, if all are returned to their original state with the same worthiness to all conflicting, what difference will there be between the virgin and the prostitute? What distinction will there be between the mother of the Lord and (it is wicked to say) the victims of public pleasures? Will Gabriel be like the devil? Will the apostles be as demons? Will the prophets be as pseudoprophets? Martyrs as their persecutors? Imagine all that you will, increase by two-fold the years and the time, take infinite time for torture: if the end for all is the same, all the past is then nothing, for what is of importance to us is not what we are at any given moment, but what we will be forever more. I am not forgetting what is often said to argue against this point, preparing hope for oneself and some kind of safety with the devil. But this is not the appropriate time to write at length against the opinion of the wicked and against the synphragma of the devil from those who teach one thing in private only to deny it in public. It is enough for me to have shown what I believe this passage signifies, and as is appropriate in a commentary, to remark briefly who the king of Nineveh is, he who is the last to hear the word of God. Just how much eloquence and secular knowledge are worth to mankind can be seen in Demosthenes, Cicero, Plato, Xenophon, Theophrastus, Aristotle and the other philosophers and orators who are considered kings and their precepts are not taken as the work of mortals but as oracles of the gods. About which Plato says, happy are those states where philosophers rule, or if kings are philosophers. How difficult it is for such men to believe in God! I am neglecting though those examples from daily life, and pass over the stories of pagans and content myself with the text of the apostle who writes in Corinthians, saying, "look, brothers, to your vocation, among you. For there are not many who are wise about their flesh, nor many powerful, or noble. But there is much madness in the world, and this is what God has chosen to confuse wise men. That which is weak in the world, this is what God has chosen to confuse strength, and that which is in the world without good birth this is what God has chosen…" [1 Cor. 1:26-8] and again he says, "I will destroy the wisdom of the wise, and I will reprove the knowledge of those who know." [Is. 29:14; 1 Cor. 1:19] And: "see that no one robs you, through philosophy, this is a vain seduction" [Col. 2:8]. From this the predication of Christ is clear, the kings of the world hear last; then they put down the clamour of eloquence and the beautiful appearance of words, they abandon themselves completely to all simplicity and rusticity, and return to the ways of peasants, sitting in the dirt and destroying what they had formerly said was good before. Let us take as an example the benevolent Cyprian: who is firstly the champion of idolatry, and had such a reputation of good speaking that he taught the art of rhetoric at Carthage. He finishes by listening to the speech of Jonah, is converted to repent and gains such courage as to preach about Christ in public and lays his neck under the sword for him. For sure we know that the King of Nineveh descended from his throne, exchanged his red gown for sackcloth, his perfumes for mud, and cleanness for uncleanness- not uncleanness of meanings but of his words. In the same way in Jeremiah it is said about Babylon that "Babylon is a golden chalice which makes all the earth drunk" [Jer. 51:7]. Which man has not been made drunk by secular eloquence? Whose spirit has not been shot through by the composition of words and by the brightness of his elegant speech? Those powerful, noble and rich have great difficulty in believing in God; then how much more so for the masters of speech! Their spirit is blinded by riches, wealth, abundance, they are prevented by their sins and cannot see their virtues; they judge the simplicity of the Holy Scripture not on the majesty of its meanings, but out of the baseness of its words. But when they who have previously taught wickedness are converted to repent and start to teach what is good then we will see the people of Nineveh converted with a single proclamation, and the speech that we read in Isaiah will come true: "is a people thus born in one go?". [Is. 66:8. LX] Men and animals are covered with sackcloth, crying out to the Lord, this is to be understood by the same meaning as this: that those who have reason and those who do not, the wise and the simple repent according to that phrase said elsewhere: "You will save men and the animals O Lord" [Ps. 35:7]. It is possible however to interpret differently the animals covered in sackcloth, especially according to those passages in which we read, "the sun and moon will be dressed in sackcloth" [Joel 2:10], and in another passage, "I will cover the heavens with sackcloth". [Is. 50:3] This will be the clothing of mourning, the worry and sadness that are designated metaphorically by sackcloth. And this phrase: "who knows if God will turn and pardon?" places us in uncertainty and doubt. Thus men in hypothetical cleanness repent with more intent and arouse even more God's mercy.

They had a covering of sackcloth at a time when, since all were mourning over the approaching destruction of the city and were clothed with the same garments, none could be accused of excessive display. (Institutes Bk 1.2)

Coarseness of attire is sometimes a sign of sorrow: wherefore those who are in sorrow want to wear coarser clothes, just as on the other hand in times of festivity and joy they wear finer clothes. Just as a man’s mind is uplifted by fine clothes, so is it humbled by lowly apparel.