In order to reflect, water must be still. The more still it is - the more exact will be the reflection. In order to be a more exact reflection of God's nature and glory, we need to be still...very still before Him. I also saw in this picture the verse where Jesus said "greater works shall you do" as the light that is reflected off the water is actually brighter than the visible sun in the sky. This is a season where those who have prepared themselves in stillness will find that they are reflecting a greater light because of the increase that He is bringing. He desires greater works from us more than we desire it, but He can not do it with those who are tossed to and fro with every wind, but can only use those who are willing to stand in quietness before Him and allow His glory to be reflected. They must also enlarge their borders so that the trees by the shore will not obscure the sun from finding it's reflection. So all the things in life that would want to grow up around us and block His light have to have their distance and we must be large enough to accommodate their need for water without draining us and making us too small to reflect the light.
Rivers are a glorious thing and needful, but sometimes God wants us to be lakes of tranquility. There is still water, there are still rocks and trees and life inside, but a different purpose and different setting. Sometimes it's about diving in and sometimes it's about floating. We can go from the river to the lake in the same day depending on the need. Sometimes even within the same hour. But both places are needful in our life. Some people stay too long at one when God is telling them to move to the other.