The Avatamsaka Sutra (The Ten Grounds):
Disciples of the Buddha, the Bodhisattva, Mahasattva, once he dwells upon the Third Ground, contemplates the marks of conditioned dharmas as they really are. That is, as impermanent, as suffering, as impure, as having no peace, as subject to destruction, as not lasting long, as produced and extinguished in a kshana, as not produced from the boundary of before, as not tending towards the boundary of afterwards, and as not dwelling in the present.
Venerable Master Hsuan Hua:
Disciples of the Buddha, all of you, the Bodhisattva Mahasattva, once he dwells upon the Third Ground, contemplates the marks of conditioned dharmas as they really are. He contemplates how all conditioned dharmas contradict true suchness. That is, as impermanent, as suffering, as impure, as having no peace. They are transitory, and do not last forever. They always entail suffering. They aren’t pure, and are not peaceful. He sees them as subject to destruction, as not lasting long, as produced and extinguished in a kshana, as not produced from the boundary of what was before, they didn’t arise from what was prior-as not tending towards the boundary of afterwards. They are not going towards what comes after…and as not dwelling in the present. They don’t dwell in the here and now either.
Venerable Master Hsuan Hua:
The Third Station of Mindfulness is to contemplate thoughts as impermanent. Thoughts of the past, present, and future cannot be got at. They are all fleeting and impermanent. Not only are thoughts of these three periods of time impermanent, all our thoughts are impermanent. I’m referring to thoughts of our ordinary human minds, not the True Mind. The True Mind is eternal, but the human mind is impermanent. Why? The human mind undergoes constant change. One thought perishes, and the next one arises. Thoughts arise and perish in endless succession, like waves on water. These infinite false thoughts are also like dust motes, bobbing up and down in the air with no fixed location. Such thoughts are impermanent. Our eternal True Mind, pure in nature and bright in substance, is permanent, constant, and unchanging.
So, the first practice is to contemplate impermanence. What is impermanent?
Every thought is impermanent. When the following thought arises, the former thought ends. When yet another thought arises, the former thought is done. There is impermanence in every thought. There is production and extinction in every thought. Therefore, you must first contemplate impermanence.
Sutra in Forty-Two Sections
Contemplating Both the False and the True
The Buddha said, "Contemplate heaven and earth, and be mindful of their impermanence. Contemplate the world, and be mindful of its impermanence. Contemplate the efficacious, enlightened nature: it is the Bodhi nature. With this awareness, one quickly attains the Way.
Venerable Master Hsuan Hua:
In the nineteenth section, the Buddha teaches us the principle that everything is made from the mind alone. We must cast aside what is false and keep what is true. Heaven covers us from above, and the earth supports us from below. Seen from the point of view of ordinary people, heaven and earth are eternal and indestructible. But, in fact, they are not eternal and indestructible. They also undergo the superseding of the old by the new. They are not permanent.
The Buddha said, "Contemplate heaven and earth, and be mindful of their impermanence." When you look at heaven and earth, you see that sometimes they are hot and sometimes cold. When the cold comes, the warmth goes. There is the cycle of spring, summer, fall, and winter. On the earth the mountains and rivers are involved in constant transition and do not stay fixed. They are dharmas that are created and destroyed. They are not the uncreated, undestroyed dharmas of the mind. They are impermanent. Therefore, the Buddha said to be mindful of their impermanence.
Contemplate the world, and be mindful of its impermanence. The world changes; it is not static. [In Chinese, the two characters for the concept "world" imply the ideas of time and place.] Both time and place are subject to creation and destruction. Neither is permanent and indestructible. So the text says, "be mindful of its impermanence."
Contemplate the efficacious, enlightened nature: it is the Bodhi nature. You contemplate your own bright, enlightened spiritual nature: it is just the Bodhi-nature. With this awareness, one quickly attains the Way. If you can investigate in this way and gain an understanding, if you can know it as it is, then you will immediately obtain the Way. Because you understand this principle, you will obtain the Way. But if you fail to understand this principle, you will not obtain the Way
Sickness, in all its forms, is suffering.
Because all dharmas are impermanent, they are also involved with suffering. Since they are all involved with suffering, they are also to be contemplated as empty and all dharmas as without self. All dharmas are empty, because they have no substantial nature. They are therefore devoid of any existence. Dharmas do not exist of themselves. There are dharmas only because there are people. If there were no people, there would also be no dharmas. All is empty and suffering and without self. Common folk are attached to the self. They can’t put down the idea of a self. If you can view all dharmas as empty, you will know that all dharmas have no self. There is nothing in reality which is the “self”, and there is nothing which belongs to the self. So don’t be attached to the self.
Time is like an arrow; the days and months fly by like a shuttlecock. The waves in the river follow one after another. Glory fades quickly. In the world, youth is followed by old age. In this way, we gradually return to the decay and extinction of old age and death, leaving no trace or shadow. Clearly, everything is impermanent.
No matter what state comes along, the cultivator does not become attached to it. When the situation passes, nothing remains. When it's gone, it's simply gone. It is said, "The mind of the past cannot be grasped, the mind of the present cannot be grasped, and the mind of the future cannot be grasped." The three minds cannot be obtained. That's why there is no attachment when they come, and no trace left when they go. They are simply received and reflected.
Light is insubstantial and immaterial. Shadows and reflections may appear to be solid, but in fact they too are insubstantial. They seem to have substance and form, but in fact they do not.
The Avatamsaka Sutra
They clearly understand and know that all that is worldly
Is like a mirage, like light, and like reflections,
Like an echo and like a dream,
Like an illusion and like transformational changes.
The holy sages enlightened to conditions
Doze high on mountain peaks alone.
Springtime's flowers wither in the fall
In a cycle of twelve interconnecting links.
The myriad things grow and prosper in the springtime, so the Pratyekabuddha sages contemplate and realize that everything undergoes the natural process of birth and death. They contemplate the hundreds of flowers blossoming in the springtime, and watch the dry leaves falling in the autumn." They contemplate the twelve causes and conditions.