These are the two belief systems that exist in our world today. These two belief systems come to the human experience via our thoughts, just as everything that has ever happened or ever will happen has come to us. All thoughts that come into our arena of thinking are based on one of two emotions. The two emotions from which all thoughts come to us are either love or fear. All thoughts that go through our heads are either love-based thoughts or fear-based thoughts.
Remember, love is the core of what God is. God is love. God is life. God, love and life are interchangeable. The process of life is the process of God experiencing love. If we all lived in the realm of the absolute, the only thoughts we would ever have would be thoughts of love because love is all there is in the realm of the absolute.
But we live in the relative physical world, so in order to know love as an experience we must also come to know the polar opposite of love, which is fear. Fear exists so that we can know and experience love.