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.

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

2729. The derivation of genuine conjugial love from good married to truth may also be evident from the fact that it cannot exist with anyone unless good united to truth and truth to good from the Lord are present in him. That derivation may also be evident from the fact that heavenly blessedness and happiness reside in that love, and that everyone in whom that love exists comes into heaven, that is, into the heavenly marriage. It is also evident from the fact that when angels are talking about the union of good and truth, that which is a representative of marriage presents itself in a lower sphere among good spirits, but that which is a representative of adultery presents itself among evil spirits. This explains why in the Word the union of good and truth is called a marriage, but the adulteration of good and the falsification of truth is called adultery and whoredom, see 2466.