'A raven,' as in Genesis 8:7, signifies falsities. The spiritual self only knows general truths from the Word, and forms its conscience from these, and the general truths of the Word are accommodated to the fallacies of the senses. So countless falsities attach themselves, and insinuate themselves into those general truths, and they cannot be drawn out. These falsities are what 'the raven which went forth in going and returning' signifies. 'Sons of the raven,' as in Psalm 147:8, 9, signify natural people in a dim light arising from fallacies relating to divine truth.

(References: Arcana Coelestia 865)

865. That 'he sent out a raven, and it went out going back and forth' means that falsities were still giving trouble is clear from the meaning of 'a raven' and from the meaning of 'going back and forth', dealt with in the paragraphs following this. Here the description is of the second state following temptation of the person who is to be regenerated, when the truths of faith start to appear as a first glimmer of light. This is the kind of state in which falsities are continually giving trouble. It is a state resembling the morning twilight when the obscurity of the night is still lingering on. That state is therefore meant here by 'the raven'. The falsities residing with a spiritual man, especially before he has been regenerated, are as thick patches of cloud, the reason being that he is incapable of knowing any truth of faith except from things that have been revealed in the Word where all things are stated in a general way. General statements there are nothing else than patches of cloud, for any one general statement embraces thousands of details, and each detail thousands of finer points. Those finer points constituting details are what light up the general statements. These have never been so revealed to mankind because they are both indescribable and also in-comprehensible, and so can neither be acknowledged nor believed. In fact they are contrary to the illusions of the senses which govern man, and to whose destruction he does not readily consent.

[2] The case is altogether different with the celestial man, who has perception from the Lord. In him details and their finer points can be implanted. Take, for example, the consideration that true marriage is a marriage of one man and one wife; and that such a marriage is representative of the heavenly marriage, and as a consequence can contain heavenly happiness, something that is not possible when one man has several wives. The spiritual man, who knows of this from the Word of the Lord, gives his assent to it and so acquires a conscience which dictates that being married to several wives is a sin. Beyond this his knowledge does not go. The celestial man however perceives thousands of details which so confirm the point that the thought of marriage to several makes him shudder. When the spiritual man's knowledge amounts to simply a general view of things, and his conscience is formed from that general view, and when the general statements of the Word are adapted to the illusions of the senses, it is clear that countless falsities which cannot be dispersed will attach themselves and worm their way in. These falsities are meant here by 'the raven that went out going back and forth'.