Water generally represents “natural truth,” or true concepts about day-to-day matters and physical things. Since all water ultimately flows into the seas, then, it follows that a sea represents a huge agglomeration of such natural truths -- usually all of the natural truth a person has, or all the natural truth a church has. Water in the sea mixes freely, and is easily stirred up by winds and currents. This is also true of the concepts we hold about natural things -- they are not all related to each other, and when relationships do exist they usually can change without damaging the concepts themselves. Many of the concepts are easily disputed, and arguments can arise like waves on the ocean -- generally with little effect other than a mixing of waters. But the sea also offers great bounty. We draw fish from it (spiritual food), float ships (doctrinal systems) on it, bathe in it (using true concepts to purify ourselves), and the water that evaporates from it and falls as rain (purer forms of truth that can attach to desires for good) makes life possible.

In Isaiah 52:14, this signifies the Lord's appearance in humility. (The Inner Meaning of the Prophets and Psalms 52)

In Lamentations 4:8, this signifies the obscurity of divine truth to such a point that it was no longer visible. (Apocalypse Explained 196[3])

In Daniel 3:19, this signifies the antagonism of people represented by ‘Babylon' against the goods and truths of the Lord's church. (The Inner Meaning of the Prophets and Psalms 174)