The gradual path of your practice and spontaneous or immediate realization, these are not actually two different things. The polarity is talked about to bring up the two aspects of realization, a provisional teaching to work with the seduction of the idea that there is something to get.
Sokuzan’s dharma talk is inspired by verse three in Vasubandhu ‘s “The Teaching of the Three Own-Beings” (Tri-svabhava-nirdesa), here as translated by Stefan Anacker: The constant state-of-not-being-found of “how it appears” in that which appears, can be known as the fulfilled own-being, because of its state of non-otherness.
Right here right now, again, don’t do the math.
It is a metaphor for whenever something occurs in life, take the attitude that you’re not going to add on your commentary, subtract from the appearance with your analysis or distract yourself.
This helps you see the way that you do the math, to see how you take a position. The only way to find reality is not to take a position on anything.
The fullness of this is what you are thinking and feeling and doing and all that is happening. It is empty of what you think it is. This fullness and emptiness that are not two are the two aspects of Suchness.
Have you noticed that the same nerve endings in in your skin sense texture that is soft or abrasive? It’s like the “nerve endings in mind”, but instead of just feeling texture we tend to tell a story about it. The minute you describe a feeling you abandon it, you miss your opportunity to see what it really is. Sit down and prioritize the awareness, the space in which things occur. If you look at the space you realize you can’t see space, but you change your allegiance from what occurs to the space itself.