(Here is another excerpt from my book, That Is That )
There is just one source for everything. It all comes from an infinite potential within existence itself. Don't take my word for it. Reach out and touch something with your hand, like a piece of furniture or other simple object. For a moment, just sense its pure existence, the simple fact that it exists. Then, sense even more deeply to feel the source of the object. See if you can sense how ultimately it is coming into existence freshly in this moment. In every instant, it is a completely new version of itself. You may be able to sense its source directly, not with your mind or through logic, but with your fingertips and with your Being.
Now touch another object and see if you can sense its source. Where is this other object's existence flowing from? You can also hold your hand out and simply touch the space in front of you. First, just experience the reality of space with your fingertips. There is a mysterious open allowing spaciousness here that everything else fits in. As you sense the wonder of the space in front of you, see if you can also feel its source. Where does space come from? Where is the space itself flowing from? Although you may not be able to sense the source of space by thinking about it or figuring it out, you may be able to directly sense the underlying source of infinite space through your fingertips and your most subtle inner sensing. It's a matter of sensing with your whole being the wonder that lies just beyond your fingertips, even when you are only touching empty space.
Now reach down and touch your own body. Once again, just sense the wonder of your body's existence. And then sense the source of that miraculous form you often call "me." Where does the body's existence come from? You can touch your legs, your face, your other hand, your hair, and with each part of your body, see if you can sense from a deeper place the infinite potential that can form itself into a living physical body. It can help to drop down and sense the body from your heart instead of from your head. This allows a fuller sensing with all of your physical and subtle senses...
To whatever degree you have a sense of the source of these various objects and of space itself, notice if there is any difference or separation between the source of the objects and your body or empty space. Is it the same source that is forming the furniture and your body? Is there any separation between the source of the space around you and the source of your body? Don't worry if this doesn't make logical sense, and simply sense with your heart the source of space and the source of your body at the same time. Are they separate or are they one and the same?
You can explore further with nonphysical experiences. Notice the flow of thoughts you are having right now. Even if you can't touch them with your fingertips, just sense their existence and their source in infinite potential. Where do thoughts come from? Where does the energy of feelings arise out of? What is the source of your desires? We are often so involved with the object or direction of our thoughts and desires that we rarely pause to consider their source.
What do you find? It's fine if you only have a vague or slight sense of the source of an object or space or your thoughts. What is this vague sense of the source like? Is it a similar sense for all of the objects and experiences that you explore? Can you find a boundary between the source of your body and the source of your thoughts? Can you find separation between the source of objects and the source of space itself?
Differences and separation are very obvious at the level of form. Your body appears very different and separate from the objects in the room you are in. It has very different qualities from the space around you, even if it is not really separate from the space around you. This is the beauty and wonder of the world of form and experience: It offers endless differences and the appearance of separation. That's what makes it possible for two forms to dance or play. But what about the source of these experiences and forms? At that level are they separate? How pronounced is the difference between the source of your thoughts and the source of your physicality? Do your body and space come from the same subtle presence that lies behind all experience and differences?
It is at the level of the source of existence that oneness is obvious and clearly true. If we look for oneness in the world of form, we can easily doubt its reality. Often at best, oneness is a vague concept we try to imagine. But if we sense the source of everything, we find that there is a deeper and infinite potential that everything comes out of and everything is made of. Then, if we continue to sense the underlying source of the various forms, we can more clearly sense their oneness even while we enjoy and appreciate their endless differences.