In Jonah 2:1-10, Jonah is trapped in the belly of the great fish. He prays for salvation, and in the end, after this terrible trial, he is vomited forth onto dry land.

Before a new church -- either a state of good and truth with a group of people, or a new state of good an truth in ourselves - can come into existence, a period of temptation, of struggle, must occur. During this time a remnant of good and truth from prior states, will be preserved. This happens to us. When we really don't want to do something that we know we should do, we get into a state of spiritual temptation. That's what this chapter is about.

In Arcana Coelestia 756, it says: "In Jonah, 'The waters closed around me, even to my soul, the deep surrounded me. Here... 'the waters' and 'the deep' stand for the full extent of temptation.

This chapter also prophesies, or foreshadows, the combats that Jesus Christ would have with the hells, and his most grievous temptations at the time. The “three days and nights during which Jonah was in the bowels of the fish,” signify the entire duration of the combat with the hells.

In the New Testament, in Matthew 12:39-41, there's a reference back to this story:

"No sign will be given to it except the sign of the prophet Jonah. For as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth. The men of Nineveh will stand up at the judgment with this generation and will condemn it, because they repented at the preaching of Jonah. And now One greater than Jonah is here.

For us, then... what? When we've turned away from the Lord, and we're in "the belly of the fish" - in temptations, struggles, combats, and everything looks pretty hopeless - then if we really pray, and seek the Lord's help, he can help us.

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

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

756. 'All the fountains of the great deep were split open' means the full extent of temptation involving things of the will. This becomes clear from what has been stated already about temptations being of two kinds, the first involving things of the understanding, the second those of the will, and about the latter being severe in comparison with the former. It is clear as well from the fact that up to now temptation involving things of the understanding has been the subject. It is similarly clear from the meaning of 'the deep' as evil desires and derivative falsities, as shown already in 18, and also in the following in the Word: In Ezekiel,

Thus says the Lord Jehovah, When I make you a city laid desolate, like the cities that are not inhabited, when I shall cause the deep to come up over you, and many waters have covered you. Ezekiel 26:19.

Here 'the deep' and 'many waters' stand for the full extent of temptation.

In Jonah,

The waters closed around me, even to my soul, the deep surrounded me. Jonah 2:5.

Here similarly 'the waters' and 'the deep' stand for the full extent of temptation.

In David,

Deep is calling to deep at the noise of Your waterspouts; all Your breakers and all Your waves have gone over me. Psalms 42:7.

This plainly stands for the full extent of temptation. In the same author,

He rebuked the Sea Suph and it became dry; He caused them to go through the deeps, as in a desert, and He saved them from the hand of him that hated them, and He delivered them from the hand of the enemy. And the waters covered their adversaries. Psalms 106:9-11.

Here 'the deep' stands for temptations in the wilderness.

[2] In early times 'the deep' meant hell, and delusions and persuasions of falsity were likened to waters and streams, and also smoke, pouring out of it. This is also what the hells of some people look like, that is to say, like deeps and like seas. These in the Lord's Divine mercy will be described later on. The evil spirits who are responsible for man's vastation, and also for temptation, come from these places. And their delusions which they infuse, and the desires with which they inflame man, are like deluges and vapours pouring out of there. For, as has been stated, man is joined to hell through evil spirits, and to heaven through angels. Consequently when 'all the fountains of the deep' are said to have been 'split open' matters of that kind are meant. The fact that hell is called the deep, and the foul things that come from there are called streams, is clear in Ezekiel,

Thus said the Lord Jehovih, On the day he went down into hell, I made him mourn, I covered the deep over him, and I restrained its streams, and the great waters were stayed. Ezekiel 31:15.

Hell is also called 'the deep' in John, in Revelation 9:1-2, 11; 11:7; 17:8; 20:1, 3.