This is difficult to understand and is going to require you to contemplate these words and validate them for yourself:
The nature of form is duality. Form includes everything perceived through the various senses as physical phenomenon. Form also includes thought and all the diversity of concepts, symbols, names, descriptions, etc.
With little inquiry, one can see that when dealing with thought-forms there is always an opposing concept, like and dislike, good and evil, right and wrong, mine and yours. Also, physical opposites are easily recognized even by small children; hot and cold, etc. Therefore, the very nature of form is dualistic.
If you make a proclamation of “truth,” if you watch closely; you will see its subtle opposing concept already built into it; and this gets labeled the enemy. In turn, one must battle the uprising of the opposite thought that continuously shows up because of the natural duality of form. So life appears to be a “battle” because you have chosen one side of the coin and are trying to forever escape the other side. Which is not possible as they cannot be separated.
Who is the witness to this play of opposites, this battle? Who is observing, seeing, and experiencing this phenomenon of form? Clearly, there is a third party here that “sees” all this. Otherwise, there would be no conscious witness to even ask such a question.
This consciousness is the You before thought, and has absolutely no connection and is unimpressed by the concepts and body sensations that belong to the reality of form. It simply reflects form phenomenon clearly and pristinely without ever getting involved or identifying with the form. Like a mirror and the images.
The mirror is completely unaffected by the images that flash across it whether the most evil and painful, or the most pleasurable and good. At the same time they cannot be separated. The mirror is always peaceful because it transcends the images, yet fully embraces them.
So, right practice is not trying to change or get rid of the images, or creating a problem with some and adhering to others; but rather knowing yourself in spite of them.
Therefore, practice diligently and earnestly with all the intensity that you can muster. As thoughts and sensations arise, relentlessly inquire:
Yes, but who am I in spite of thought? Who am I in spite of these sensations in this body?
Then who you “think and feel you are” dies, and you discover that you are the Still Eternal Changeless Surface that reflects moving transient ever changing images.