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.

302. This was the reason why mysteries of faith were never revealed to the Jews. Being what they were they were not even explicitly told that they would live after death, nor explicitly told that the Lord would come into the world to save them. Indeed they were kept in such ignorance and stupidity, and are so still, that as a result they did not know and still do not know of the existence of the internal man, or of anything internal at all. For if they had known it then, or were to know it now, so as to acknowledge it, they would profane it and in so doing would have no hope at all of salvation in the next life. This is what the Lord meant in John,

He has blinded their eyes and hardened their heart, lest they see with their eyes and understand with their heart, and are converted and I heal them. John 12:40.

Also, the Lord spoke to them in parables, and without explaining any to them, 'lest seeing they might see, and hearing they might hear, and understand', as He declares in Matthew 13:13. For the same reason all mysteries of faith were concealed from them and hidden beneath the representatives of their Church, and it was for the same reason that the prophetical style took the form it did. It is one thing however to know and another to acknowledge. Anyone who knows but does not acknowledge is in the same position as one who does not know, whereas anyone who does acknowledge and after that speaks blasphemy and practises profanation is what the Lord was referring to.