23. Nothing is more common in the Word than for the word 'day' to be used to mean the particular time at which events take place, as in Isaiah,

The day of Jehovah is near. Behold, the day of Jehovah comes. I will make heaven tremble, and the earth will be shaken out of its place, on the day of My fierce anger. Its time is close at hand, and its days will not be prolonged. Isaiah 13:6, 9, 13, 22.

And in the same prophet,

Her antiquity is in the days of antiquity. On that day Tyre will be forgotten for seventy years, like the days of one king. Isaiah 23:7, 15.

Since 'day' stands for the particular time it also stands for the state associated with that particular time, as in Jeremiah, Woe to us, for the day has declined, for the shadows of evening have lengthened! Jeremiah 6:4

And in the same prophet,

If you break My covenant that is for the day and My covenant that is for the night, so that there is neither daytime nor night at their appointed time. Jeremiah 33:20, 25.

Also,

Renew our days as of old. Lamentations 5:21.

In the Word, “light” in the highest sense represents Divine Truth: knowledge, ideas, understanding that come to us from the Lord. In lesser degrees -- the light of a lamp, the light of the moon and so forth -- it represents lower levels of truth, ideas and understanding drawn from more earthly sources. Also, the sun in the Word represents the Lord, with its heat representing the divine love and its light representing the divine wisdom. That wisdom flows into our minds and enters our lives in the form of truth -- things we can know and ponder that lead us and help us to be good people. This connection between light and thought is one of many spiritual/natural relationships that's embedded in our common language. People “see the light” when they understand something; we try to “shed some light” by bringing new thoughts to a difficult question; people are “enlightened” when they get new information or a more complete understanding of something. And a light bulb in a cartoon represents an idea!