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.

5114. 'And on the vine three shoots' means derivatives from this even to the final one. This is clear from the meaning of 'the vine' as the understanding part, dealt with immediately above in 5113; from the meaning of 'three' as complete and continuous even to the end, dealt with in 2788, 4495; and from the meaning of 'shoots' as derivatives; for since 'the vine' means the understanding part, 'shoots' means nothing else than derivatives from this. Because 'three' means that which is continuous even to the end, that is, which goes from first to last, 'three shoots' means derivative degrees extending from the understanding part to the final level, which is that of the senses. The first in the sequence is the actual understanding part, and the last is the senses. In general the understanding part is the sight which the internal man possesses and which sees by the light of heaven radiating from the Lord; and everything it sees is spiritual or celestial. But the senses, in general, belong to the external man; and here the sensory power of sight is meant because this corresponds to and is subordinate to the understanding part. The sensory power of sight sees by the light of the world radiating from the sun; and everything it sees is worldly, bodily, or earthly.

[2] In the human being there exist derivatives from the understanding part that dwells in the light of heaven; and they extend to the senses which dwell in the light of the world. Unless these derivatives existed the senses could not possess any life of a human quality. A person does not owe the life which his senses possess to what he sees by the light of the world, for the light of the world holds no life within it; he owes it to what he sees by the light of heaven, for this light does hold life within it. When the light of heaven falls on the perceptions a person has gained by the light of the world, it brings life to them and enables him to see objects in an intelligent manner, and thus as a human being. In this way a person possessing factual knowledge born from things which he has seen and heard in the world, and therefore from those which have entered in through the senses, comes to possess intelligence and wisdom, on which in turn he bases his public, private, and spiritual life.

[3] As regards derivatives specifically, the nature of their existence in a person is such that no brief explanation of them is possible. They exist as degrees, like steps, from the understanding part down to the senses. But no one can have any conception of those degrees unless he knows how they are related to one another, that is to say, that they are quite distinct and separate from one another, so distinct that interior degrees can come into being and remain in being without exterior ones, but not exterior degrees without interior ones. For example, a person's spirit can remain in being without a material body, as it also actually does when death separates it from the body. For a person's spirit exists in an interior degree, his body in an exterior one. Similarly with a person's spirit after death. If he is one of the blessed his spirit exists in a final and outermost degree when in the first heaven; in a more interior degree when in the second; and in the inmost one when in the third. When it exists in the inmost it exists at the same time in the other degrees, though these are inactive with him, almost as the human body is inactive during sleep, but with this difference that interiorly angels are at such times fully awake. Therefore as many distinct and separate degrees exist in the human being as there are heavens, apart from the final one, which is the body and the bodily senses.

[4] From all this regarding a person's spirit one may gain some idea of the way derivatives are related to one another from the first to the final one, that is, from the understanding part to the senses. A person's life, which he receives from the Lord's Divine, passes through these degrees from the inmost to the final one. At every degree there exists a derivative of that life which becomes increasingly general, until in the final degree it is the most general. Derivatives in the lower degrees are merely combinations - or to put it more appropriately, structured forms - of the individual and particular constituents of the higher degrees ranged consecutively, with the addition of the kinds of things drawn from purer nature, and after that from grosser nature, that can serve as containing vessels. Once these vessels are done away with, the individual and particular constituents of the higher degrees, which had received form in those vessels, move back to the degree immediately above. And because in the case of the human being there is a link with the Divine, and his inmost being is such that it can accept the Divine - and not only accept but also make Him its own, by acknowledging and having an affection for the Divine, thus by a reciprocal response to Him - and because he thereby has the Divine implanted within him, he can never die. Indeed what is eternal and infinite exists with him, not only through their flowing into him but also through his reception of them.

[5] From this one may see how uninformed and senseless in their thinking regarding the human being those people are who compare him to animals and imagine that he will not be alive after death any more than they are. Such people do not take into consideration the fact that with animals there is no acceptance of the Divine or any acknowledgement or affection leading to a reciprocal response to the Divine by making Him their own, or any consequent joining to Him. Nor do those people take into consideration the fact that, as the animal state is like this, the recipient forms of life which these possess are inevitably dissipated; for with animals that which flows into them passes through their organic forms into the world, where it comes to an end and melts away, never to make any return there.