Light
In the Word, “light” in the highest sense represents Divine Truth: knowledge, ideas, understanding that come to us from the Lord. In lesser degrees -- the light of a lamp, the light of the moon and so forth -- it represents lower levels of truth, ideas and understanding drawn from more earthly sources. Also, the sun in the Word represents the Lord, with its heat representing the divine love and its light representing the divine wisdom. That wisdom flows into our minds and enters our lives in the form of truth -- things we can know and ponder that lead us and help us to be good people. This connection between light and thought is one of many spiritual/natural relationships that's embedded in our common language. People “see the light” when they understand something; we try to “shed some light” by bringing new thoughts to a difficult question; people are “enlightened” when they get new information or a more complete understanding of something. And a light bulb in a cartoon represents an idea!
Water
Water is the basis of life, the essential ingredient in all drinks, and in the form of rivers, lakes and oceans supports life in myriad ways. The spiritual meaning of water is similarly basic: It represents truth in general, the ideas and concepts that guide us to do good things in our lives. In a more specific sense, it represents truth at its simplest level: the ideas we learn from the Bible and simply believe. Swedenborg refers to this as “natural” truth or “truths of faith.” They are not things we have explored, figured out or confirmed through life; rather they are things that we accept to be true because we’ve been told they are true. Like water, these ideas flow to us from other sources. And like water, they are ever-changing; to build something permanent we might look to the more permanent ideas represented by stones. But water is crucial to life, and so are these accepted ideas. Water can also, of course, be threatening. Rivers, lakes and oceans are inherently dangerous, and flooding was an ever greater threat in Biblical times than it is now. These aspects represent the opposite meaning – water as falsity, twisted ideas which support evil and can overwhelm and destroy us if we’re not careful.