When you become conscious be Being, what is really happening is that Being becomes conscious of itself. When Being becomes conscious of itself, that’s presence. Since Being, consciousness, and life are synonymous, we could say that presence means consciousness becoming conscious of itself, or life attaining self consciousness. But don’t get attached to the words, and don’t make an effort to understand this. There is nothing that you need to understand before you can become present.
In the Bible, God declares : “I am the Alpha and the Omega, and I am the living One.” In the timeless realm where God dwells, which is also your home, the beginning and the end, the Alpha and the Omega, are one, and the essence of everything that ever has been and ever will be is eternally present in an un-manifested state of oneness and perfection, totally beyond anything the human mind can ever imagine or comprehend. In our world of seemingly separate forms, however, timeless perfection is an inconceivable concept. Here even consciousness, which is the light emanating from the eternal source, seems to be subject to a process of development, but this is due to our limited perception. It is not so in absolute terms.
Everything that exists has Being, has God-essence, has some degree of consciousness. Even a stone has rudimentary consciousness; otherwise, it would not be, and its atoms and molecules would disperse. Everything is alive. The sun, the earth, plants, animals, humans – all are expressions of conciseness in varying degrees, consciousness manifesting as form.
Reference : The Power of Now. Eckhart Tolle.