Thoughts on Oneness, from the chapter "Eighth Week: Mindfulness in Objects of Mind" of Andrew Weiss's Beginning Mindfulness:
... When we truly experience non-self and impermanence, our illusion of being separate falls away and we contact the ground of being from which all things arise and pass away. In the "I/you" world in which we live we encounter the reality of nonduality when we truly experience that we cannot separate ourselves as the perceivers from what we perceive or ourselves as the thinkers from what we are thinking. The personal identification slips away; the fear is at once "my" fear and, simply, fear, part of the common ground of being. In this nondualistic world, the world of mindfulness, there is no "I/my/me," no labeling, no personalizing. Once this door is open, we can simply be present in mindfulness, aware of what is going on, and even for brief moments, as we experience the nonduality inside our dualistic world, not even being aware that we are aware. In Zen, this experience of mindfulness is expressed: "In the seeing, only what is seen. In the hearing, only what is heard. In the touching, only what is touched. In the feeling, only what is felt. In the thinking, only what is thought."
When we "get" the reality of all this in our being, we encounter life as it is. I have noticed that those who truly have lived this awareness, even if only for a moment, soften a bit around the edges. In my own life, my experience of this has helped me open my heart and be more loving, kind, understanding, and compassionate. For me, it is very simple: Everything makes up me, I am part of everything. I am the result of causes and conditions that I and countless others create, and I create causes and conditions for myself and countless others. I know that all things change when causes and conditions change, and that brings up the desire to make as many as I can of these causes and conditions ones that promote peace and love. To manifest this in my daily life, I must cultivate the space and activity of mindfulness, where the words, and my own personal narrative, drop away. This lies deep at the heart of the Buddha's teachings on mindfulness. Here we can touch life directly, outside of notions, concepts, and beliefs. Here we can embrace the heart of the cosmos.