It is necssary to purify the defilements in our mind in order to see the truth

Everything is pure. For us to see things through a pure perceptions is almost impossible. But this doesn’t mean such thing doesn’t exist. Therefore, practicing Varjayana means one tries to develop pure view. One must try [to do] this, otherwise, we are always in samsara, in suffering; there’re no good things, only bad things. So, practicing Varjayana means to see everything is pure. But we don’t believe they are pure. That [thinking] is not true. The truth is that there is purity in all phenomena, but since mind is polluted by ignorance and we are not able see everything is pure. Now you have to understand: “Oh my view is wrong, my perception is polluted. Because of that I have to purify my negative thoughts.” If you understand that, if you try to practice in that way then only that way you can make some improvements.
But if you believe whatever you see, whatever to hear is real, truly-established, you’ll never get anywhere; in fact, you develop grasping at all phenomena. Therefore, you need to purify yourself: body, speech and mind [and] especially the negativities in the mind, impurity of the mind. That is [you are] really someone who is doing actual practice. If someone is not doing that, someone is doing the opposite of that, that’s not a Dharma practitioner.

Hungkar Dorje Rinpoche, “Devotion To Guru Rinpoche – Key To Siddhis”