Buddha-nature and ignorance, liberation and birth and death, Nirvana and Samsara: these are not separate things; there are no dichotomies. We may speak as a matter of convention of leaving ignorance and gaining enlightenment, but when one is truly enlightened, one realizes that ignorance and Buddha-nature are one and the same. If ignorance and Buddha-nature truly existed as permanent, separate realms, then an ignorant person would never discover his Buddha-nature; he would remain ignorant, and would be unable to attain enlightenment. But this is not the case. Ignorance and Buddha-nature are not separate.
In making the transition from ignorance to Buddha-nature, you will realize that ignorance does not really exist. If it did, we would all be bound to it forever. Anyone practicing who understands this principle will not strive to get rid of ignorance or seek after Buddha-nature.
When you practice, and your body tires and your mind fills with turmoil and vexation, it is easy to start struggling with yourself. If you oppose weariness and vexation, then you will only become more tired and create more vexations. You will lose heart. It is better if you say to yourself, "This is 'ignorance and ignorance itself is Buddha-nature. I won't resist. I won't get angry. I won't fight my condition." If what you experience is Buddha-nature, then what is there to hate or fight? But when you sit, you will suffer pains, fatigue and wandering thoughts. While you are suffering, it will be hard to believe the things I say. It is difficult to relax and allow things to be as they are. You may even think that these obstacles arise precisely because you are practicing the Way ─ that somehow, the pains have a mind of their own, and they are waiting for you to sit and meditate. When you become enlightened, you will realize that vexations are Buddha-nature, and in fact, ignorance does not exist.