This quote by E. Stanley Jones speaks to the idea that life is inherently enough. It suggests that life is currently equipped with the necessary resources to live a fulfilling life. This might mean that life is currently geared up with the required tools to be effective, or that life is currently filled with pleasure and satisfaction. It could likewise mean that life is already loaded with love and empathy, and that we don't need to look for these things outside of ourselves. Eventually, this quote is a pointer that life is currently filled with what we need, and that we don't need to look in other places for satisfaction. It encourages us to appreciate the life we have and to make the most of it.
"Life is life - whether in a cat, or dog or man. There is no difference there between a cat or a man. The idea of difference is a human conception for man's own advantage"