1983. Evil spirits most vehemently desire and burn to infest and attack man when he is sleeping, but man is then especially guarded by the Lord, for love does not sleep. The spirits who infest are miserably punished. I have heard their punishments oftener than I can tell; they consist in rendings (spoken of, n. 829, 957, 959), under the heel of the left foot, and this sometimes for hours together. Sirens, who are interior enchantresses, are they who are especially insidious in the night time, and then try to insinuate themselves into a man's interior thoughts and affections, but are as often driven away by the Lord by means of angels, and are at last deterred by the severest punishments. They have also spoken with others in the night time, exactly as if they spoke from me, and as it were with my speech, so like that it could not be distinguished, pouring in filthy things, and persuading false ones.
 I was once in a very sweet sleep, in which I had nothing but soft repose. When I awoke, some good spirits began to chide me for having (as they said) infested them so atrociously that they supposed they were in hell-throwing the blame upon me. I answered them that I knew nothing whatever about the matter, but had been sleeping most quietly, so that by no possibility could I have been troublesome to them. Astonished at this, they at last had a perception that it had been done by the magic arts of sirens. The like was also shown afterwards, in order that I might know the quality of the crew of sirens.
 They are chiefly of the female sex, who in the life of the body had studied to allure male companions to themselves by interior artifices; insinuating themselves by means of outward things, captivating their lower minds in every possible way, entering into each one's affections and delights, but with an evil end, especially that of exercising command. Hence they have such a nature in the other life that they seem able of themselves to do all things, imbibing and inventing various arts, which they absorb as easily as sponges do waters, whether clean or filthy. So do they imbibe and put into act things profane as well as holy, with the end, as before said, of exercising command. It has been granted me to perceive their interiors, and to see how foul they are, being defiled by adulteries and hatreds. It has also been granted me to perceive how powerful in its effects is their sphere. They reduce their interiors into a state of persuasion, in order that these may conspire with their exteriors toward such things as they intend. They thus compel and violently draw spirits to think exactly as they do.
 No reasonings appear in connection with them, but they make use of a kind of simultaneous rush of reasonings that are breathed into the person's evil affections and so they work by applying themselves to the natural inclinations, and thereby they get into the lower minds of others, whom they lead on, and by persuasion either overwhelm or captivate them. They study nothing more than to destroy the conscience, and when it is destroyed they get possession of men's interiors, and even obsess the men, although these are ignorant of it. At this day there are not as formerly external obsessions, but there are internal ones, by spirits of this class. They who have no conscience have become obsessed in this way. The interiors of their thoughts are insane in a manner not unlike this, but are concealed and veiled over by an external decorum and a pretended honorableness, for the sake of their own honor, gain, and reputation. And this such men may know, if they pay attention to their thoughts.