9597. 'With cherubs' means the Lord's watchfulness, guarding it from the approach of the hells and the harm they can do. This is clear from the meaning of 'cherubs' as watchfulness and providence, preventing any approach to the Lord except through good and protecting from harm the good from the Lord which exists in heaven and with man, dealt with in 9509, consequently guarding heaven from the approach of the hells and the harm they can do.

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.