Sea
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.
Apocalypse Revealed # 492
492. "Clothed in sackcloth." This symbolizes the grief experienced meanwhile over the truth's not being accepted.
Being clothed in sackcloth symbolizes grief over the destruction of truth in the church, for garments symbolize truths (nos. 166, 212, 328, 378, 379). Consequently to be clothed in sackcloth, which is not a garment, symbolizes grief over the lack of truth, and where there is no truth, there is no church.
The children of Israel represented grief in various ways, which, because of their correspondence, were symbolic. For example, they would put ash on their heads, roll around in the dust, sit on the ground for a long time in silence, shave themselves, beat their breasts and wail, rend their garments, and also clothe themselves in sackcloth, and so on. Each action symbolized some evil in the church among them for which they were being punished. Then, when they were being punished, they put on a representation of repentance in these ways, and because of their representation of repentance, and at the same time then of their humbling themselves, they were heard.
[2] That putting on sackcloth represented grief over the destruction of truth in the church may be seen from the following passages:
The lion has come up from his thicket... He has gone forth from his place to make your land desolate... For this, clothe yourself with sackcloth, lament, wail. (Jeremiah 4:7-8)
O daughter of my people, gird yourself in sackcloth and roll about in ashes! ...For the destroyer will suddenly come upon us. (Jeremiah 6:26)
Woe to you, Chorazin (and) Bethsaida! For if the mighty works which were done in you had been done in Tyre and Sidon, they would have repented... in sackcloth and ashes. (Matthew 11:21, Luke 10:13)
After the king of Nineveh heard the words of Jonah, he "laid aside his robe, covered himself with sackcloth and sat in ashes." Moreover, he proclaimed a fast and ordered that "man and beast be covered with sackcloth." (Jonah 3:5-8)
And so on elsewhere, as in Isaiah 3:24; 15:2-3; 22:12; 37:1-2; 50:3; Jeremiah 48:37-38; 49:3; Lamentations 2:10; Ezekiel 7:17-18; 27:31; Daniel 9:3; Joel 1:8, 13; Amos 8:10; Job 16:15-16; Psalms 30:11; Psalms 35:13; 69:10-11; 2 Samuel 3:31; 1 Kings 21:27; 2 Kings 6:30; 19:1-2.