The Brightness and Ignorance

Bodhisattva Kasyapa said to the Buddha: "Oh World Honored One! You, the Buddha, say that there is cream in milk. What does this mean? Oh World Honored One! If there's definitely cream in milk and if it is true that it cannot be seen because of the minuteness of its size (concentration), how can we say that the cream comes about through the causal relations of milk? When things originally have no the root element, we can say that a thing is born. If it already exists, how can we say that life arises? This is the case that, if there is definitely cream in milk, there must be milk in all the grasses. Likewise, there must be grass into milk as well. If the situation is that there is definitely no cream in milk, how could the cream come from outside of the milk? If there is no root element, but it appears later, how could be that grass does not grow in milk?”

"Oh good man! Do not say that there is definitely cream in milk or that there is not cream into milk. Also, do not say that it comes from outside (of milk). If there is definitely cream in milk, how can it be a different thing and have a different taste? That is why you should not say that there's definitely cream in milk. If there is definitely no cream in milk, why is it that something different does not come about in the milk? If poison is put into milk, the cream will kill a person. This is why you should not say that there is definitely no cream in the milk. Moreover, if we say that cream comes from outside, why is it that the cream does not come about from water? For this reason, do not say that the cream comes from anywhere else. Oh good man! As the cow feeds on grass, its blood changes into white. Grass and blood die and the power of the virtue of beings change them, and we gain milk. This milk comes from grass and blood, but we cannot say that there are two (in milk). All we can say is that the conditions (relations) make it happen. This we can say. From cream up to sarpirmanda, things go thus. The case [here] is the same. Because of this, we may rightly say that there is the taste of the cow. This milk dies away, and in consequence, there comes about cream. What is the condition? It is sour or warm. For this reason, we can say that it (the cream) comes from conditions. The situation is the same with the others, up to sarpirmanda. For this reason, we cannot say that definitely there is no cream in milk. If it comes from somewhere else, it must exist separately from the milk. This cannot be. Oh good man! The same is the case with the brightness and ignorance. [About that which is] bound up by all illusions, we say ignorance. If are linked to all good things, there may be brightness. That is why we say that there can be no two things. So, I said: 'There is a grass in the Himalayas called pinodhni, which, if eaten by the cow, produces sarpirmanda'. The same is the case with the Buddha-Nature.

Oh good man! The beings are sterile in fortune and do not come across this grass. The same applies to the Buddha-Nature. As the defilements overspread them, beings cannot see it. For example, the water of all great oceans has the same salty taste, but it holds out the best of water, as in the case of milk. Also, the Himalayas are perfect in many virtues and produce various medicines, but there are also poisonous weeds. It is the same with the bodies of all beings. There are the four poisonous serpents, but is also present the great king of the all-wonderful medicine. The so-called Buddha-Nature is not something that has been created. Simply, it is overspread by defilements. Only a person who thoroughly cuts them away - whether be it a Kshatriya, Brahmin, Vaishya and Sudra - sees the Buddha-Nature and attains unsurpassed Enlightenment.

Read More on the Nirvana Sutra, Chapter 12 - On the Nature of the Tathagata.