In chapter 4 of the Book of Amos, verses 1-3 are talking about people who pervert the truths of the church. They will fall into falsities in outermost things.

In the Bible, fish represent "lower" things than mammals, so we can interpret the fishhooks in verse 2 as meaning being caught and held fast in natural or lower things.

Verses 4-6 are about acts of worship such as tithes and sacrifices. These look similar to genuine worship, but are only external sorts of things. We can tell because ‘teeth’ (in verse 6) represent ultimates or outermost things (see Secrets of Heaven 6380). It follows that “cleanness of teeth” would mean outermost things that look good but only imitate genuine worship. The Lord exhorts, “Yet you have not returned to me.”

Verses 7-8. Some things true will remain, when where there are too many false ideas, the truths don't get through. This can be seen where the Lord says, “I made it rain on one city; I withheld rain from another city... where it did not rain the part withered.” Again the Lord exhorts, “Yet you have not returned to me.”

Verse 9. Afterward all things of the church are falsified, shown by blight attacking the gardens, vineyards, fig tree and olive trees. The last three represent spiritual, natural and celestial things, or all the things of spiritual life. “Yet you have not returned to me,” says the Lord.

Verses 10-11. The Lord explains the devastating things he allowed to happen: plague in Egypt, death of young men by swords, stench in the camps, Sodom and Gomorrah. This is because they are profaned by sensual knowledges. Profanation means the mixing of good and evil together. (See Secrets of Heaven 1001[2]).

This extends to all things of the church, with the church being the Lord’s kingdom on earth (Secrets of Heaven 768[3]).

With profanation “as soon as any idea of what is holy arises, the idea of what is profane joins immediately to it,” (Secrets of Heaven 301).

Now there is hardly anything left. “Yet you have not returned to Me,” says the Lord again.

Verses 12-13: Because people adamantly remain in their profane ways, they are warned, “Prepare to meet your God!”. This is the God powerful and mighty, “who forms mountains, and creates the wind,” and even more close to home, “Who declares to man what his thought is.” As intimately a knowing as that is, the Lord’s love for all humanity is contained in His exhortations for them to turn themselves to Him.

See, for example, Luke 6:44-45, and True Christian Religion 373.

496. These have power to shut heaven, so that no rain falls in the days of their prophecy. (11:6) This symbolically means that people who turn away from these two essential elements of the New Church cannot receive any truth from heaven.

Heaven here means the angelic heaven. Thus the rain symbolizes truth for the church from there. Consequently to close heaven so that no rain falls means, symbolically, that people cannot receive any truth for the church from heaven. Truth for the church from heaven is doctrinal truth from the Word.

We are told that the two witnesses have the power to shut heaven, but as in no. 494 above, the meaning here is not that they have that power, but that people who turn away from the two essential elements of the New Church close heaven to themselves, because they continue to be caught up in their falsities.

That rain symbolizes Divine truth from heaven is clear from the following passages:

My doctrine shall drop as the rain, My word shall fall as the dew... (Deuteronomy 32:2)

(If) you... serve other gods..., (Jehovah will) shut up heaven so that there be no rain... (Deuteronomy 11:16-17, see also 11:11, 11:14)

I will lay waste (My vineyard).... I will also command the clouds that they rain no rain on it. (Isaiah 5:6)

The showers have been withheld, and there has been no late rain. Yet you continue to have a harlot's forehead... (Jeremiah 3:3)

For as the rain comes down... from heaven..., so shall My word (go) forth from My mouth. (Isaiah 55:10-11)

Rejoice then, you children of Zion, and be glad in Jehovah... For He has given you seasonable rain in righteousness. (Joel 2:23)

You have caused to drop, O God, a kindly rain... (Psalms 68:9)

He shall come down like rain upon the grass of the meadow... In His days the righteous shall flourish... (Psalms 72:6-7)

He will come to us as rain, as the late... rain waters the earth. (Hosea 6:3)

...my word shall rain down on them, and they will wait for me as for the rain, and they will open their mouth for the late rain. (Job 29:22-23)

Son of man, say...: "You are a land that is not cleansed, which will have no rain in the day of wrath. There is a conspiracy of her prophets in her midst... (Ezekiel 22:24-25)

And so on elsewhere, as in Isaiah 30:23; Jeremiah 5:24; 10:12-13; 14:3-4; 51:16.

A flooding rain stands for the destruction of truth in Ezekiel 13:11, 13-14; 38:22. For temptation or trial in Matthew 7:24-27.