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.

3563. 'And said, The voice is Jacob's voice, and the hands Esau's hands' means that the understanding consists in this case of truth existing inwardly, while the will consists in this case of good existing outwardly, so that an inversion of order exists with them. This is clear from the use of 'voice' to refer to truth and of 'hand' to refer to good. For 'voice' is used in reference to truth, as is evident from the places introduced in Volume One, in 219, 220, and from the fact that the actual words used are 'the voice is Jacob's voice', Jacob representing natural truth, as shown in various places above. And the reason why 'hand' is used in reference to good is that 'the hand' means power and ability, 878, 3541, the source of which is nothing other than good. All the power and ability that truth possesses comes from good, even though it seems to come from truth. This likewise is evident from the fact that the actual words used are 'the hands are Esau's hands', Esau representing natural good, as also shown above. The consequent existence of an inversion of order with them is evident from the consideration that proper order requires good, which belongs to the will, to exist inwardly, and truth, which belongs to the understanding, to exist outwardly. But these matters, as stated above, are such as can hardly be explained in any intelligible way because few have any knowledge of such things. For even if a perfectly clear explanation of them were given they would still not be understood if knowledge of them is lacking. Nevertheless the matter must be discussed since it is the subject at this point.

[2] The only source of the good of the natural which manifests itself in a person is interior good, that is, the good of the rational. Natural good can have no other source, though that which flows in from the one determines the nature of the good in the other. And since the good of the natural comes from no other source, neither does the truth of the natural, for where good is, so also is truth. Both must be present if they are to be anything at all. And again, that which flows in determines the nature of the truth there. Influx is such that the good of the rational flows into the natural along two different routes - one a very short and thus direct route into the good itself of the natural, and then on through the good of the natural into the truth there, this good and this truth being represented by Esau and his venison. In addition to this, the good of the rational flows into the natural along a second route which is less short, that is to say, through the truth of the rational, by means of which influx it forms something resembling good, but which in fact is truth.

[3] Everything is thus taking place according to order when the good of the rational flows directly into the good of the natural and at the same time into the truth there, and also indirectly by way of the truth of the rational into the good of the natural, and in a similar way both directly and indirectly into the truth of the natural. When all this is taking place the influx is according to order. Such is the influx with those who have been regenerated. But a different influx exists prior to regeneration, as has been stated above. That is to say, the good of the rational does not flow into the good of the natural directly but indirectly, by way of the truth of the rational, and so manifests something resembling good in the natural, which is not genuine good nor consequently genuine truth. Instead it is something such as does indeed possess good inmostly by virtue of influx through the truth of the rational; but there is nothing more. Therefore good too presents itself there under a different form, that is to say, outwardly as good represented by 'Esau' but inwardly as truth represented by 'Jacob'. And as this is not in accordance with order an inversion of order is said to exist with them. Yet insofar as nobody can be regenerated in any other way it is according to order.

[4] I realize that no matter how clearly these matters are stated and as a consequence are able to be perceived clearly by those who have a knowledge of the existence of such things, they still remain obscure to those who do not know what influx is, more so to those who do not know that the rational is distinct and separate from the natural, and more so still to those who do not have any distinct and clear idea of what good is or of what truth is. But the nature of natural good and of natural truth in the state prior to regeneration is plain to see only from the desires present at that time. When a person desires truth not because he has life in view but some other ends, such as to become learned, and to become this because of some desire to outdo others, which amounts to childish envy, and also because of some desire for glory, the order existing with the good of the natural and the truth of the natural is akin to that represented here by Jacob. As these two exist in relation to each other, there is a reversal of order, that is to say, the will, to which good belongs, exists outwardly, while the understanding, to which truth belongs, exists inwardly.

[5] But in the state following regeneration the situation is different. In this case the person desires truth not only because he has life in view but more still because he desires the good itself which constitutes that life. Previous desires, that is to say, those connected with outdoing, with childish envy, and with glory, now break away, so much so that they seem so to speak to have been dispelled. At this point good which belongs to the will exists inwardly, and truth which belongs to the understanding exists outwardly. The result then is that truth acts as one with good since it stems from good. This order is genuine order. The order existing previously also serves to bring this order about, for the will which at that time occupies an external position allows many things to come in which contribute to regeneration, like a sponge which absorbs water, clear or muddy, so that it absorbs such things as would otherwise be rejected. Indeed these things serve as means and also as ideas that have to be formed concerning genuine goods and truths, besides other uses which they serve.