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.

3635. In the human body there are two organs which are the mainsprings of its entire movement, and also of every action and external or purely physical sensation - the heart and the lungs. These two so correspond to the Grand Man or Lord's heaven that celestial angels there constitute one kingdom, and spiritual angels the other, for the Lord's kingdom is celestial and spiritual. The celestial kingdom consists of those who are governed by love to the Lord, the spiritual kingdom of those who are governed by charity towards the neighbour, 2088, 2669, 2715, 2718, 3235, 3246. The heart and its kingdom in man corresponds to celestial angels, the lungs and their kingdom to spiritual ones. Also the angels flow into things belonging to the heart and lungs, so much so that these things receive their being and are kept in being by means of that influx from them. But the correspondence of heart and lungs with the Grand Man will in the Lord's Divine mercy be presented as a separate subject.