It is the principle of correspondence - or proportion and correspondence - in the Kybalion.
Perhaps the most popular of the seven hermetic principles of Kybalion
1908 document that claims to be the essence of the teachings of Hermes the Trismegistus, who, according to myth, was Abraham's teacher.
Each chapter of the Kybalion is devoted to each of the seven principles or axioms that are considered universal laws. This school of thought dates back thousands of years, however, we can apply the principles it describes quite well to modern reality.
The principle expresses the idea that there is always a correspondence between the laws of phenomena of the various levels of existence and life and maintains that because of the harmony that exists between the physical, mental and spiritual levels, all levels of existence are connected and in correspondence. The macrocosm is in the microcosm and vice versa. In other words, solar systems, societies and life on Earth are all the same.
Kybalion's correspondence principle states that what we do at the microcosm, we will do at the macrocosm. Therefore, even the smallest actions affect the grand scheme of our behavior. By doing anything, we do everything. Any action in one area of our lives will likely affect all others. Kind of like the effect of a butterfly's flight.
We can take the principle of responsiveness even further and argue that our outer world is a reflection of our inner world.
The thoughts and images we have in our consciousness appear, in many cases subconsciously, in our outer world. The mind takes everything as it is. In other words, it is difficult for it to distinguish between illusion, belief and reality. It confuses interpretations with facts and begins to recreate exactly what we focus on most.
The outer world reflects our inner setting and everything is a reflection of what we are hiding inside. The inner world is the cause, the outer world is the effect. For the effect to change, the cause must change.
"The inner world is the world of our demands and our actions and our structure and our capabilities that responds to the outer world. And the external world is the realm of our embodiment. That's where we are. At the point where the inner and outer worlds meet is the seat of the soul".-Joseph Campbell