Do me a favor. This is something to be experienced yourself, don't just read the words.
On the next bright, beautiful sunny day go outside, sit in a field and lay out a perfectly white sheet. Sit in a field that has trees, flowers and all kinds of stuff. Sitting comfortably on the sheet, just be aware of the sheet, your surroundings, the sun in the sky above. Just relax.
You will notice as the winds stir that your sheet starts to collect a lot of dirt and debris. You might get some leaves and flower petals, some insects trekking across your sheet. Your once perfectly white sheet will actually start to look rather untidy.
So there are a couple things we can do about this.
The first method is to be constantly mindful of anything that stains our sheet and then strive diligently to clear it. Using this method our mindfulness is paramount and we actually may be able to keep the sheet clear for a period of time. Invariably though more dirt and debris will arise and we will keep ourselves busy in the clearing process.
This is the method of the causal vehicles. The vehicles based on mind. They do enable one to recognize and experience the pure nature of the mind, but they are bound by their fixation on defilements and impurity.
The second method is to just rest and continue to watch as our sheet starts to collect debris. As we continue to identify with the originally clean and white sheet, not reacting to anything whatsoever, we start to notice that the debris doesn't actually defile the sheet. Actually, as the winds continue to stir the debris moves around on the sheet and can even remove itself if we wait patiently. The debris starts to become an ornament, magically dancing around the purity of our perfectly white sheet.
This is the method of Dzogchen, the Great Perfection. If we can identify and recognize the originally pure nature of our own minds, then there is really nothing to do but rest in openness. The resting without fixation is actually what allows the liberation of the defilements, if there are any defilements to begin with.
In this example, sitting outside represents resting in openness. The perfectly white sheet represents our originally pure nature of mind. The stirring winds represent the constantly changing process of dependent origination; cause and effect. The trees, flowers and stuff represent our reality- often times beautiful but also messy. The insects trekking across the sheet represents our own neurosis, ugly and disgusting. The dirt represents all of our thoughts and emotions, fears and insecurities.
Oh, and if you want to leave the sheet that is your own anxiety and doubt. Just relax and stay seated.
Be the sheet.