圓同太虚 Perfect it is, like vast emptiness
無欠無餘 With nothing wanting, nothing superfluous
良由取捨 When you grasp this and reject that
所以不如 You cannot see its suchness
That singleness is known as emptiness, wherein the universe does not exist in the beginning, end or middle, but by which the universe is pervaded at all times. – Adi Shankara
This Mind is no other than Buddha: there is no Buddha outside of Mind, nor is there Mind outside of Buddha. This Mind is pure, and like space it has no distinct forms. As soon as you raise a thought and begin to form an idea of it, you ruin the reality itself, because you then attach yourself to form. Since the beginningless past there is no Buddha who has ever had an attachment to form.
It is told again by the Tathagata that this Reality is perfectly uniform and undifferentiated. By Reality is meant Bodhi (enlightenment). That is, this pure Mind that is the source of all things is the very same in all sentient beings, in all the Buddha-lands, and also in all the other worlds, together with mountains, oceans, etc., forms and formless things. They are all the same, and there are no characteristics that distinguish this object from that. This pure Mind, the source of all things, is always perfect and illuminating and all-pervading. People are ignorant of this and take what they see or hear or think of or know for Mind itself; their insight is then veiled and unable to penetrate into the essence itself, which is clear and illuminating. When you realize no-mind (wu-hsin) without any interference, the essence itself is revealed to you. It is like the sun coming out: its illumination penetrates the ten quarters and there is nothing that will obstruct its passage. (Suzuki, 1935, p. 81)
D. T. Suzuki. Manual of Zen Buddhism, 1935.