{Footnote 1} All light in the heavens is from the Lord as a sun (n. 1053, 1521, 3195, 3341, 3636, 3643, 4415, 9548, 9684, 10809).  The Divine truth that goes forth from the Lord appears in heaven as light, and furnishes all the light of heaven (n. 3195, 3222, 3223, 5400, 8644, 9399, 9548, 9684).

128.  The Divine truth is light to the angels because the angels are spiritual and not natural.  Spiritual beings see from their sun, and natural beings from theirs.  It is from Divine truth that angels have understanding, and their understanding is their inner sight, which flows into and produces their outer sight; therefore in heaven whatever is seen from the Lord as the sun is seen in light.{1} This being the source of light in heaven the light is varied there in accordance with the reception of Divine truth from the Lord; or what is the same, in accordance with the intelligence and wisdom in which the angels are, thus differently in the celestial kingdom and in the spiritual kingdom, and differently in each society.  In the celestial kingdom the light appears flaming because the angels there receive light from the Lord as a sun; but in the spiritual kingdom the light is shining white, because the angels there receive light from the Lord as a moon (see above, n. 118).  So, too, the light differs in different societies, and again in each society, those that are at the center being in greater light and those in the circumference in less light (see n. 43).  In a word, the angels have light in the same degree in which they are recipients of Divine truth, that is, are in intelligence and wisdom from the Lord;{2} and this is why the angels of heaven are called angels of light.

  {Footnote 1} The light of heaven illumines both the sight and
  the understanding of angels and spirits (n. 2776, 3138).

{Footnote 2} The light in heaven is in harmony with the intelligence and wisdom of the angels (n. 1524, 1529, 1530, 3339).  Differences of light in the heavens are as many as there are angelic societies; and as there are in the heavens endless varieties of good and truth, so are there of wisdom and intelligence (n. 684, 690, 3241, 3744, 3745, 4414, 5598, 7236, 7833, 7836).

129.  As the Lord in the heavens is Divine truth, and the Divine truth there is light, so in the Word He is called Light, likewise all truth is from Him, as in the following passages: 

     Jesus said, I am the light of the world; he that followeth
     Me shall not walk in darkness, but shall have the light of
     life (John 8:12).

     As long as I am in the world I am the light of the world
     (John 9:5).

Jesus said, Yet a little while is the light with you.  Walk while ye have the light, lest darkness overtake you.  While ye have the light believe in the light, that ye may be sons of light.  I have come a light into the world, that whosoever believeth in Me may not abide in darkness (John 12:35, 36, 46).

     Light has come into the world, but men have loved the
     darkness rather than the light (John 3:19).