In the third chapter of the Book of Jonah, Jonah finally reaches Nineveh, and starts preaching repentance and reformation to the people there. And... they listen! Even the King of Assyria listens!

The inner meaning of the story is pretty close to the surface here, and there's important symbolism. Swedenborg summarizes the chapter's meaning in this one sentence:

"The nations, hearing from the Word of God about their sins, and that they would perish, were converted after repenting, and were heard by the Lord, and saved." (The Inner Meaning of the Prophets and Psalms 213)

Rev. George McCurdy, in his exegesis of this chapter, offers this summary:

The great city of Nineveh has many spiritual representations. The world saw Nineveh as a mighty nation, but in the eyes of the Lord, it represented the shallowness and weakness (death) of false doctrines, contrived beliefs confirmed by the proprium (self love), the fallacies of the senses, and the unenlightened understanding that spawns spiritual ignorance.

The Lord’s mercy and love for all prompted Him not only to send His message to Nineveh, but to ensure that it would be preserved for eternity. Jonah’s call to "arise and go" preach to Nineveh is a call for spiritual renewal. It is a call for repentance. The fasting, sackcloth, and ashes symbolize a call to be aware that "where there is no truth, there is no church."

Where the Word is closed, and not loved, there is a loss of conjunction with the Divine resources. The fasting of man and beast symbolizes a need for the spiritual and natural appetites to come to the Lord for that "bread which comes down from heaven." The Ninevites giving up their natural food and drink represents their turning away from "as-of-self" concepts and reminds all who read and hear the Word of the Lord to rely on heavenly manna.

"Why do you spend money for what is not bread, and your wages for what does not satisfy? Listen carefully to Me and eat what is good, and let your soul delight itself in abundance…" (Isaiah 55:2)

The king sitting in ashes and mourning represents a sorrowful attitude toward "the remains of the fire of self-love." Repentance involves self-examination, making oneself guilty for the sins and evils committed, asking the Lord for His help, and desiring to attain a new life.

As we mull over this concept, think about the Lord’s preaching on earth. As He went about His mission, He often used these words: "You have heard it said of old… but I say unto you…" Putting aside human traditions and taking on the Lord’s teachings is an ongoing effort. Jonah was told to preach the words of the Lord. He was not to make things up from his memory. He was to be a true and faithful prophet of the Lord’s ways.

Here's a link to an interesting (audio) sermon on this chapter, by Rev. Todd Beiswenger.

Rev. Martin Pennington suggests two explanatory passages from Swedenborg's theological writings:

"Forty days means a period of temptation combats or severe change." (Arcana Coelestia 730)

"A fast represents those who are in a state of unhappiness when good is no longer joined to the truths." (Arcana Coelestia 9182[10])

Other references of interest listed by Rev. McCurdy include:

"As ‘forty’ signified what is full or complete… forty signifies what is complete in respect to instruction and influx… for this reason it was said by Jonah to the Ninevites that ‘the city would be overthrown after forty days" (Jonah 3:4) (Arcana Coelestia 9437[2])

"By being clothed in sackcloth is signified mourning on account of the vastated truth in the church; for garments signify truths; and therefore, to be clothed in sackcloth, which is not a garment, signifies mourning that there is no truth; and where there is no truth, there is no church." Jonah 3:5-6 is cited. (Apocalypse Revealed 492)

"…the rite of putting sackcloth on the loins to testify…mourning may be seen from the historic and prophetic parts of the Word, as in… Jonah 3:5-8… for a sign representative of mourning over the evil on account of which Nineveh was to perish; thus over destroyed good." (Arcana Coelestia 4779[2])

"From the signification of garments it is also manifest why they rent their garments, when any one spoke against the Divine truth of the Word… and why, on account of transgressions against Divine truths, they put off their garments, and put on sackcloth." Jonah 3:5, 6, and 8 are cited. (Apocalypse Revealed 166)

"That ‘ashes’ denote falsity, may be confirmed from passages where another word for ‘ashes (cinis)’ is used, for these ashes have a like origin…" Jonah 3:6 is cited. (Arcana Coelestia 7520)

"…by ‘ashes’ in the opposite sense, namely, what is condemned that remains after the burning from the fire of self love. This is signified by ‘the ashes’ which they carried on the head, and in which they rolled themselves when bewailing their sins." Jonah 3:6 is cited. (Arcana Coelestia 9723)

"In the spiritual sense by kings those who are in truths are signified, by the great ones those who are in goods, by the rich those that are in the knowledge of good, by the mighty they that are in erudition, by servants they that are in such things from others, and thus from memory, and by freemen they that are in such things from themselves…" Jonah 3:7 is cited. (Apocalypse Revealed 337)

"The interior good and also the interior evil…are signified by ‘man,’ are those which are of the intention or end, for the intention or end is the inmost of man; but the exterior good and also the exterior evil which are signified by ‘beast,’ are those which are of the thought, and of the consequent action when nothing stands in the way…By ‘beast,’…in respect to the external or natural man, a man is nothing else than a beast, for he takes delight in the like cupidities and pleasures, as also in the like appetites and sense…Therefore… from a holy rite it was commanded by the king of Nineveh, that both man and beast were to fast, and were to be covered with sackcloth (Jonah 3:7, 8)." (Arcana Coelestia 7523)

"… in the spiritual world a man’s affections appear at a distance like beasts… and beasts, viewed in themselves, are nothing but forms of natural affections… By man and beasts together is signified man as to spiritual and natural affection, in the following passages… Jonah 3:7, 8…" (Apocalypse Revealed 567)

"Here ‘webs’ and ‘garments’ are predicated of things of the understanding, that is, of the thought; ‘iniquity’ and ‘violence,’ of things of the will, that is, of works. In Jonah 3:8… the ‘evil way’ is predicated of falsities, which are of the understanding; and ‘violence,’ which are of the will." (Arcana Coelestia 623[2])

"…the ‘wrath of anger’ is attributed to Jehovah, and consequently ‘repentance.’" (Arcana Coelestia 588[2])

"…the Word is such in the sense of the letter, it may be evident that it cannot be understood without doctrine. But let examples illustrate this. It is said that Jehovah repenteth (Jonah 3:9; 4:2), and it is also said that Jehovah repenteth not (Num. 23:19…): without doctrine these statements do not agree." (Teachings Regarding the Sacred Scripture 51)

"In these passages (Jonah 3:9,10) Jehovah is said to have ‘repented,’ when yet it cannot be that He repents, because He knows all things before He does them; from which it is evident that by ‘repenting’ is signified mercy." (Arcana Coelestia 10441[2-4])

Finally, here's a link to Rev. McCurdy's study guide for the Book of Jonah, which is available for free as a .pdf, for your use.

2240. That 'cry' is falsity, and 'sin' evil, becomes clear from the meaning of 'cry' in the Word. The meaning of 'cry' as falsity is not seen by anyone unless he knows the internal sense of the Word. The expression occurs several times in the Prophets, and when vastation and desolation are the subject in those places it is said that men 'wail and cry out', meaning that goods and truths have been laid waste. In those places a word is used by which in the internal sense falsity is described, as in Jeremiah,

The voice of the cry of the shepherds, and the wail of the powerful ones of the flock, for Jehovah is laying waste their pasture. Jeremiah 25:36.

Here 'the cry of the shepherds' means that they are subject to falsity, which leads to vastation.

[2] In the same prophet,

Behold, waters rising out of the north, they will be a deluging stream, and they will deluge the land and all that fills it, the city and those who dwell in it, and men will cry out and every inhabitant of the land will wail, on the day that is coming to lay waste. Jeremiah 47:2, 4.

This refers to the desolation of faith which is effected by falsities. 'A deluging stream' is falsity, as shown in Volume One, in 705, 790.

[3] In Zephaniah,

The voice of a cry from the fish gate, and a wailing from the second quarter, and a loud crash from the hills. And their wealth will be for plunder, and their houses for desolation. Zephaniah 1:10, 13.

Here also 'a cry' has reference to falsities that lay waste.

[4] In Isaiah,

On the road to Horonaim they will raise a cry of ruination, for the waters of Nimrim will be desolations, because the grass has withered, herbage is at an end, there are no plants. Isaiah 15:5-6; Jeremiah 48:3.

Here the desolation of faith is meant, and the climax is described by 'a cry'.

[5] In Jeremiah,

Judah mourned and her gates languished; the people were in black down to the ground, and the cry of Jerusalem went up. And their illustrious ones sent their lesser ones to the waters; they came to the pits, they found no water, they returned with their vessels empty. Jeremiah 14:2-3.

Here 'the cry of Jerusalem' stands for falsities, for their finding no water means lack of cognitions of truth - 'water' meaning such cognitions, as has been shown in Volume One, in 28, 680, 739.

[6] In Isaiah,

I will rejoice in Jerusalem and be glad in My people; and no more will there be heard in it the voice of weeping nor the voice of a cry. Isaiah 65:19.

Here 'there will not be heard the voice of weeping' means that there will be no evil, 'nor the voice of a cry' that there will be no falsity. The majority of these details cannot be understood, nor thus what is meant by 'a cry', from the sense of the letter, but from the internal sense.

[7] In the same prophet,

Jehovah looked for judgement, but behold, rottenness; for righteousness, but behold, a cry. Isaiah 5:7.

This also is referring to the vastation of good and truth. Here, as also in various places in the Prophets, a kind of reciprocity is expressed, which is such that one finds evil in place of truth, meant by 'rottenness' instead of 'judgement', and falsity in place of good, meant by 'a cry' instead of 'righteousness'; for by 'judgement' is meant truth and by 'righteousness' good, as shown above in 2235.

[8] A similar reciprocity is expressed in Moses when Sodom and Gomorrah are referred to,

From the vine of Sodom comes their vine, and from the fields of Gomorrah their grapes; they have grapes of poison and clusters of bitterness. Deuteronomy 32:32.

Here a similar manner of expression occurs, for 'the vine' is used in reference to truths and to falsities, 'fields and grapes' to goods and to evils, so that 'the vine of Sodom' means falsity derived from evil, and 'fields and grapes of Gomorrah' evils derived from falsities. For there are two kinds of falsity, dealt with in Volume One, in 1212, and so also there are two kinds of evil. Both kinds of falsity and evil are meant in this verse by 'the cry of Sodom and Gomorrah has become great, and their sin has become extremely grave', as is clear from the fact that 'cry' is mentioned first and 'sin' second, and 'Sodom', which is evil springing from self-love, is referred to first, and 'Gomorrah', which is falsity derived from that evil, is referred to second.