In Daniel 4:15, 25, 33; 5:21, this signifies truth from good or falsity from evil; if truth, it is the truth of peace and innocence, because dew appears in the morning. (Arcana Coelestia 8455)

The number "four" in the Bible represents things being linked together or joined. This is partly because four is two times two, and two represents the ultimate linking between our desire to be good and our understanding of truth. We can also see this in the fact that most buildings are rectangular, with the four sides linking together to make a whole. We also divide directions into four -- north, east, south and west -- and talk about the "four corners" of something meaning all of it. So our special thinking naturally looks at four sides as linking together into a whole.

(References: Apocalypse Explained 417; Arcana Coelestia 1686, 9103, 9601, 9767, 9864)