The Law of Divine Oneness is the foundational law, according to which absolutely everything in our universe is interconnected. In other words, every choice, word, desire, and belief you have will also have an impact on the world, and on the people in your life.
Sometimes this impact will be immediate and obvious. At other times, it may take a while to manifest, or you may never even discover that it has occurred. Try to think of yourself as part of everything around you to live in accordance with this law. We are all one, and awareness of this makes us more powerful as well as more empathetic.