7870. 'On that night' means their state - a state of evil. This is clear from the meaning of 'night' as a state when there is nothing but evil and falsity. For night describes the opposite of day and thick darkness the opposite of [clear] light, and 'day' and '[clear] light' mean a state in which truth and good reign. This being so, 'night' also means the last phase of the Church, for at that time falsities and evils reign because there is no faith or charity, see 2353, 6000. In addition 'night' means when vastation is completed, 7776, and also damnation, 7851. From all this it is evident that the state of those who are in hell is called 'night'. Not that the thick darkness of night envelops them, for they can see one another. But since the state of truth and good which exists in heaven is called 'day', the state of falsity and evil is called 'night'. Also thick darkness exists in hell when any light at all from heaven flows into it; for then the inferior light which they see by is reduced to nothing and becomes thick darkness.

[2] The source of the inferior light they see by is, it is true, light from the Lord coming through heaven; for in the next life no light comes from anywhere else. But among those in hell that light from Him enters by way of the ability to understand what is true. The ability enabling them to understand remains with them, as it does with every human being, however much they may be steeped in evil or falsity. But when that heavenly light passes on into their will - that is to say, into unwillingness to understand - and consequently passes into the evil and falsity that reside with them, the heavenly light is turned for them into inferior light resembling that emitted from a coal fire. And, as has been stated, that inferior light is converted into utterly thick darkness by the light of heaven when this flows into it. Regarding the inferior light in hell, its being like that emitted from a coal fire, see 1528, 3340, 4418, 4571; and regarding its conversion into thick darkness at the presence of the light of heaven, 1783, 3412, 4533, 5057, 5058, 6000. From all this it may be recognized that in the next life the kind of light each one has depends on whether his ability to understand is furnished with truths springing from good or with falsities arising from evil.

3340. Existing as the opposite of that light is thick darkness, and as the opposite of that warmth is coldness. Within that thick darkness and that coldness dwell those in hell. Their thick darkness is the product of the falsities in which they are immersed, and their coldness the product of evils. And the further away they are from truths the thicker is their darkness; and the further away they are from good the more intense is their coldness. When one is allowed to see into the hells where such beings exist the very dark mist in which they live is visible. And when there is any exhalation from that mist the insane ideas flowing from falsities, and the forms of hatred from evils, are detected. They are also provided sometimes with a light, but this is the feeble light from an ignis fatuus, which however goes out on them and becomes thick darkness as soon as they look at the light of truth. In addition they are sometimes provided with warmth, but this warmth is like that of a filthy bathhouse, which however turns into coldness with them as soon as they detect any hint of good. A certain spirit was sent into that dark mist which envelops those in hell so that he might discover for himself what it is like with those who are there. But the Lord protected him by means of angels. From there he spoke to me and said that the maniacal rage against what is good and true, and above all against the Lord, was so great that he was astounded that it could ever be withstood. For those in hell were breathing out nothing else but all kinds of hatred, revenge, and murder, and doing so with such vehemence that they wanted to destroy everybody throughout the universe. Consequently if the Lord was not constantly driving back that rage the entire human race would perish.