With Chan practice, we can realize our mind or our original face. One of the Chinese characters for “realizing” is “參 (can)”. It is used to explore and discover the original face that is devoid of fabricated notions. It is the nature of the mind without any elaborations. In Chan, the mind is described as “naked”. The qualities of the mind are luminosity and emptiness. Hence, it is also called the “primordial awareness”.
Dharma practice is to exercise our awareness. Speaking of awareness, there are two features: First, to know and to realize. Second, it is formless and notionless. We need to understand this mind that is not a physical heart. It is unarising and unceasing. The mind is free from creation, duration, dissolution, and the state of being dissolved. We are trying to uncover the unchanging mind that has never disappeared or stolen.
The mind could also be understood as the Kalachakra, cycles of time. The mind cannot perish as time goes by. Time is simply a phenomenon of concept. The indestructible nature of the mind is called, "vajra". This vajra-like mind cannot be destroyed by any means even in the concept of time. The vajra mind can annihilate all the obscurations, karmic obstacles, and cyclic existence.
The purpose of Dharma practice is to be free from the samsaric suffering. Take what we've learned and observe the various sufferings in this world. When we're sick, no one else could suffer on our behalf but ourselves. Be mindful of these sufferings and observe the working of the unfailing karmic principle. Naturally, we'd value the importance of diligent Dharma practice. In this life, we are very fortunate to come across Dharma, the teaching on enlightenment. Now, we need to be clear and habitualize what we should strive to accomplish.
Chan means that “not one dharma is substantial”. What does it mean? Fundamentally, eternalism and nihilism are the wrong understanding of the nature of dharmas. “Not one dharma is substantial” refers to the essence of the mind. That being said, when we're fixated with one dharma or a notion, the mind becomes defiled with stains. Yet, the truth is that the mind is free from any stains. As well, it is free from any blockages. There is no tent, no cover, no wall to veil the mind. If we fixate on an idea, it is like "adding another head atop of the head", a redundancy. So, we should come to realize this very mind and get to know its original face. This is a work of exploring and getting to know the truth.