Eph 5:13: But everything exposed by the light becomes visible—and everything that is illuminated becomes a light.
In Vs 13, Paul then uses a familiar theme in Jewish thought. He also gives them a little scientific truth. Everything that is exposed by the light becomes visible. Years ago I lived in Hay River. When the snow fell it covered everything and made it look pretty but in the spring when the snow melted you could see the imperfections of the landscape and in many parts of the community, you saw the junk and material people stored in their yards. Men do not like the light because it exposes them to who they are.
Paul then reveals that when something is exposed to light if it has certain qualities it can illuminate or reflect the light. On clear sunny days, colors become more bright and beautiful. The sky is brighter and bluer. The grass is greener and the trees more beautiful. As the moon reflect the light our lives should reflect and shine for the Lord.