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.

5335. 'And Joseph was a son of thirty years' means a state when the quantity of remnants was complete. This is clear from the meaning of 'thirty' as a completed number of remnants, dealt with below, and from the meaning of 'years' as states, dealt with in 482, 487, 488, 493, 893. In the Word the number thirty can mean some existence of conflict, or else it can mean a completed number of remnants. The reason why that number has this twofold meaning is that it is arrived at by multiplying five and six, or else by multiplying three and ten. When it is the product of five times six it means some existence of conflict, 2276, because 'five' means some, 649, 4638, 5291, and 'six' conflict, 720, 737, 900, 1709. But when thirty is the product of three times ten it means a completed number of remnants, because 'three' means that which is complete, 2788, 4495, and 'ten' means remnants, 576, 1906, 2284. A composite number implies much the same as the simple ones of which it is the product, 5291. Remnants are the truths joined to good which have been stored away by the Lord in a person's interior parts, see 468, 530, 560, 561, 576, 660, 1050, 1738, 1906, 2284, 5135.

[2] A completed number of remnants is likewise meant by 'thirty' - as it is also by 'sixty', and by 'a hundred' too - in Mark,

The seed which fell into good ground yielded fruit growing up and increasing. One bore thirty-fold, and another sixty, and another a hundred. Mark 4:8, 10.

Each of these numbers, being a multiple of ten, means a completed number of remnants. Also, because no one can be regenerated - that is, permitted to enter into spiritual temptations, by means of which regeneration is effected - until he has received a completed number of remnants, it was therefore laid down that no Levite should carry out any work in the tent of meeting until he was fully thirty years old. Their work or function is also called 'military service', being referred to in Moses as follows,

Take a census of the sons of Kohath from the midst of the sons of Levi - from sons thirty years of age and over, up to sons fifty years of age, everyone coming to perform military service, to do the work in the tent of meeting. Numbers 4:2-3.

Much the same is said regarding the sons of Gershon, and much the same regarding the sons of Merari, in verses 22, 23, 29, 30, and then in verses 35, 39, 43. Of that same chapter in Moses. And something similar is implied where it says that David began to reign when he was a son thirty years of age, 2 Samuel 5:4.

[3] From all this one may now see why the Lord did not make Himself known until He was thirty years of age, Luke 3:23. At that age a completed number of remnants existed with Him, though these remnants which the Lord possessed were ones that He Himself had acquired for Himself. They were also Divine ones and the means by which He united His Human Essence to His Divine Essence and made that Human Essence Divine, 1906. In Him therefore lies the reason why 'thirty years' means a state when the quantity of remnants is complete and why the priests the Levites began to perform their specific functions when they were thirty years old. And because he was to represent the Lord's kingship, David did not begin to reign until he was that same age. For every representative is derived from the Lord, and therefore every representative has reference to Him.