In the Word, 'Satan' signifies people who are caught up in the pride of self-derived intelligence.

'Satan' 'the devil,' and 'the prince of the world,' signify hell. (True Christian Religion 116)

(Referencat: Apocalypse Revealed 97, 841)

97. "'But are a synagogue of Satan.'" This symbolically means, because as to doctrine they are caught up in falsities.

They are termed a synagogue because they call themselves Jews, and since Jews taught in synagogues, a synagogue symbolizes doctrine. Moreover, because Satan means a hell composed of people caught up in falsities, therefore they are termed a synagogue of Satan.

Hell is called the Devil and Satan, and a hell called the Devil means people there who are caught up in evils - properly speaking, people caught up in a love of self. And Satan means people there who are caught up in falsities - properly speaking, people caught up in a conceit in their own intelligence.

These hells are called the Devil and Satan because all who are in them are called devils and satanic spirits.

It can be seen from this now that their being a synagogue of Satan means, symbolically, that as to doctrine they are caught up in falsities.

[2] Still, because the subject here is people who as to life are engaged in good, but as to doctrine are caught up in falsities, and these do not know otherwise than that they are engaged in good and that their falsities are true, we must say something about them.

Every good pertaining to worship is formed in accordance with truths, and every truth is formed from good. Therefore goodness without truth is not good, nor is truth without goodness true. In outward form, indeed, they appear as though they were, but still they are not.

We call the union of goodness and truth the heavenly marriage. It is this that forms the church in a person and that forms heaven in him. Consequently if falsities are substituted for truths in a person, he then does the good of falsity, which is not good, being either pharasaic or merit-seeking, or something natural inborn.

[3] But let examples serve to illustrate:

Someone caught up in the falsity of believing that he does good of himself because he has the ability to do good - his good is not good, because he is at the core of it, and not the Lord.

Someone caught up in the falsity of believing that he can do good that is good without recognizing any evil in himself, thus who acts without repentance - such a person, when doing good, does not do good, because without repentance he is prompted by evil.

Someone caught up in the falsity of believing that good purifies him of evils, unaware of any of the evils that motivate him - the only good that he does is spurious good, which is inwardly contaminated with his evils.

Someone caught up in the falsity of believing in the existence of more than one god, who confirms himself in that belief - the good that he does is a fragmented good, and a fragmented good is not good.

Someone caught up in the falsity of believing that the Divine does not reside in the Lord's humanity like the soul in its body cannot do good from the Lord, and good that does not come from the Lord is not good, for it is contrary to these words of the Lord:

(If anyone does not abide in Me, and I in him, he cannot bear any fruit,) for without Me you can do nothing. If anyone does not abide in Me, he is cast out as a branch (that is) withered; and (it is thrown) into the fire, and... burned. (John 15:4-6)

The like is found in many other places. For good takes its character from truths, while truths take their essence from good.

[4] Who does not know that the church is not a church without doctrine? And the doctrine must teach a person how to think about God and from God, and how to behave from God and with God. Therefore the doctrine must be composed of truths, according to which the person does what is called good. It follows from this that to act in accordance with falsities is not good.

People suppose that the good that a person does has in it nothing derived from truths or falsities, when in fact the character of the good is due to nothing else; for the two go together like love and wisdom, and also like love and foolishness. A wise person's love is what does good, while a foolish person's love does something like it outwardly, but something altogether unlike it inwardly. A wise person's good is accordingly like pure gold, while a foolish person's good is like excrement overlaid with gold.