Apocalypse Explained # 243
243. And white garments, that thou mayest be clothed, signifies genuine truths and intelligence therefrom. This is evident from the signification of "white garments," as being genuine truths, for garments signify truths (See above, n. 195), and "white" signifies what is genuine, and is predicated of truths (See above, n. 196); also from the signification of "to clothe," as being to acquire intelligence for oneself therefrom, for by means of genuine truths all intelligence is acquired; for the human understanding is formed to receive truths, therefore it becomes such as the truths are out of which it is formed. It is supposed that understanding is also the ability to reason from thought and to speak from falsities, and to confirm falsities by many arguments; but this is not understanding, it is only a faculty granted to man with the memory to which it is adjoined, and of which it is an activity. Yet by means of this faculty the understanding is born and formed, so far as man receives truths from affection; but genuine truths it is not possible for any man to receive from affection except only from the Lord, since they are from Him; consequently, to receive understanding, or to become intelligent, is not given to any man, except only from the Lord, but it is given to everyone who applies himself to receive (according to what was said above, n. 239. This, therefore, is signified by "I counsel thee to buy of Me white garments, that thou mayest be clothed."
Arcana Coelestia # 9570
9570. 'And let it cause its lamps to go up' means the light of the spiritual heaven. This is clear from the meaning of 'causing the lamps to go up' as kindling a light in them so that they may give light; and since 'the lampstand' represented the spiritual heaven, 9548, 'causing the lamps to go up' means the light of the spiritual heaven. The light of the spiritual heaven is Divine Truth emanating from the Lord, and the faith, intelligent understanding of truth, and wise discernment of good that spring from it, see the places referred to in 9548. What the light of the spiritual heaven is like must be stated briefly. In the Lord's celestial kingdom, which is the inmost or third heaven, there is light which is vastly superior to the light that exists in the Lord's spiritual kingdom, which is the middle or second heaven. The light of the celestial kingdom or inmost heaven does not have the appearance of light but of flame. The reason for this is that in that heaven the good of love reigns, and the good of love manifests itself visually in heaven as flame, whereas in the Lord's spiritual kingdom, which is the middle or second heaven, there is light which, though vastly superior to the light of the world, nevertheless has the appearance of brilliant light. And the reason why is that in this heaven the truth of faith springing from the good of love reigns, and the truth of faith springing from that good manifests itself visually in heaven as brilliant light. This also explains why 'light' in the Word means truth that springs from good, and in the highest sense Divine Truth emanating from the Lord's Divine Good. From all this it may now become clear what should be understood by the light of the spiritual heaven, and what by the flame of the lamp from which that light shines.