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.

7779. 'From Pharaoh's firstborn who is to sit on his throne' means falsified truths of faith that occupy the first place. This is clear from the meaning of 'firstborn' as faith, dealt with in 352, 2435, 6344, 7035; from the representation of 'Pharaoh' as factual knowledge in general perverting the Church's truths, dealt with in 6015, 6651, 6679, 6683, 6692, so that 'Pharaoh's firstborn' is faith consisting of such truths, that is, faith consisting of falsified truths of faith; and from the meaning of 'throne' as the rule of truth, and in the contrary sense the rule of falsity, dealt with in 5313. The fact that 'Pharaoh's firstborn who is to sit on his throne' means falsified truths of faith that occupy the first place is evident from the use of the words 'even to the firstborn of the servant-girl who is behind the mill', which mean falsified truths of faith that occupy the very last place; besides which the king's son means that which is primary since the king is the head.

[2] Falsified truths occupying the first place are those which are taken to be essential truths, such as these: Faith saves a person irrespective of the life he has been leading; it saves a person in the final hour of his life; he is at that point pure and free from sins, which means that these are removed in an instant like dirt on the hands by water. Those falsified truths posit that faith does exist without charity, that so far as a person's salvation is concerned it does not matter what kind of life he leads, and also that a person who is a devil can become an angel of God in an instant. Such notions and others like them are the falsified truths occupying the first place; those that are immediately derived from them occupy the second place; and those which are remotely derived from them occupy the last place. For every truth has a long wide-ranging sequence of derivations, some of which are in a direct line from it, some at an angle, while those that merely touch on that truth stand on the outermost edges.

[3] The fact that such notions and others like them are falsified truths of faith is very plain to see. Does anyone who thinks properly not know that the life of faith makes a person spiritual, not faith except to the extent that it has been integrated into his life? A person's life is his love, and what he loves, that he wills and intends; and what he wills and intends, that he does. This is the essential nature (esse) of the person, not what he knows, or what he thinks but does not will. That essential nature of a person cannot possibly be changed into a different one by his thinking about mediation and salvation, only by new birth, which is being effected throughout a large part of his life. For he must be conceived, be born, and mature anew; and this is not effected by thinking and speaking, but by willing and acting.

[4] These matters have been stated because 'Pharaoh's firstborn' and 'the firstborn of the Egyptians' mean faith separated from charity, which - as has been shown in what has gone before - is not faith but the knowledge of such things as constitute faith. The reason why 'the firstborn of the Egyptians' represented that kind of faith is that the Egyptians, more than all others who constituted the representative Church after the time of the Flood, possessed a knowledge of the religious observances of the Church, 4749, 4964, 4966, 6004. At that time all ceremonies were representative of spiritual realities in heaven. The Egyptians had a greater knowledge of these than all others had; but in course of time they began to love merely their knowledge of them. They now began to think, as one finds at the present day, that the Church consisted entirely in knowing the kinds of things that have to do with the Church, and no longer in a charitable life. Thus they turned the whole order of the Church upside down; and once this had been turned upside down truths which are called the truths of faith were inevitably falsified. For if truths are applied in ways contrary to Divine order - as happens when they are applied to evils, or in the case of the Egyptians to acts of magic - they are no longer truths with those people but acquire from the evils to which they are applied the nature of falsities.

[5] Let the calf-worship among Egyptians serve to illustrate this. They knew what a calf represented, namely the good of charity. As long as they knew this and had this in mind, then when they saw calves, or when they prepared calves at charitable feasts, such as the ancients held, or later on when calves were used in sacrifices, they thought in a way that was sane and at the same time in company with the angels in heaven since a calf is for them the good of charity. But when they began to make calves of gold, place them in their temples, and worship them, they thought in an insane manner and at the same time in company with the hells. In that way they turned a true representative into a false one.