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.

1695. That 'all their food' means the power to think what was false is clear from the meaning of 'food'. What the celestial, spiritual, and natural food are which people enjoy in the next life has been shown already in 56, 58, 680, 681. These also correspond to food for the body, and therefore they are also represented in the Word by food and are actually called food. The food of evil and hellish spirits however is that which is the reverse of wisdom, intelligence, and true knowledge, namely all falsity; and what is remarkable, evil spirits are also sustained by this food. The reason they are sustained by it is that it is their life. Unless they are given the opportunity to revile the truth, and indeed to blaspheme it, they cannot live. Yet they are not given the freedom to think and speak anything false except that which subsists from their own evil; they are not free to think or speak that which is contrary to their own evil, for this is deception. Insofar as their own evil is the origin of the falsity they express, their own life is the source of it; and in this case it is also forgiven them, since their nature is such that they could not otherwise live at all.

[2] With regard to their being stripped of the power to do evil and to think falsity, the situation is that in the conflicts brought about by temptations evil spirits are permitted to draw forth all the evil and falsity residing in a person, and to fight from that person's evil and falsity. But once they have been overcome they are no longer allowed to do so, for, being within that person, they instantly perceive that good and truth have been confirmed. Such perception exists more completely with spirits than with men. From the very sphere of a person confirmed in truth and good they recognize in an instant what the situation is, what response they will get, and much else. This is quite clear in the case of a spiritual and regenerate person, with whom evil spirits are present just as much as they are with one who is not regenerate; but with the regenerate person they have been subdued and are subservient. These are the things meant by their being stripped of the power to do evil and to think falsity.