The river represents life and the people yelling represents philosophies and idea’s, trying to explain what you cannot see or feel.
There is a river. On one side it appears to be dangerous and rushing. On the other it is a calm, gentle stream.
A man yells at his friend on the other side of the river to simply cross over, but his fear of the river sweeping him away makes him resist.
This can tell us that truth or truths can be clouded from our vision or we can be afraid of the truth when after all the truth is not that bad!