Mazu Daoyi (709–788) was Huineng's dharma grandson — trained by Huairang, who was trained by Huineng himself. He became the most influential Chan master of the Tang dynasty, and his most famous teaching can be stated in four characters: jixin jifo (即心即佛).
即心即佛. Mind is Buddha. Your mind, right now, is the Buddha-mind.
What It Doesn't Mean
It doesn't mean your thoughts are sacred. It doesn't mean your ego is enlightened. It doesn't mean you can skip practice because you're already perfect.
What it means is: the awareness in which thoughts arise — that awareness is already Buddha-nature. You don't need to cultivate it, attain it, or earn it. It's what you already are, before you add anything to it.
The Radical Move
This was revolutionary. Before Mazu, Chinese Buddhism was largely about gradual cultivation — purifying the mind, accumulating merit, studying scriptures. Mazu said: stop polishing. The mirror is already bright.
He didn't reject practice. He rejected the idea that practice adds something to what's already there. Practice doesn't make you a Buddha. It reveals that you always were one.
The Later Teaching
Famously, Mazu later told a student: "Not mind, not Buddha." When asked about this contradiction, he said: "I use 'not mind, not Buddha' to cure sickness caused by 'mind is Buddha.' If there is no sickness, then medicine is also not needed."
This is Chan at its most characteristic: using words to destroy words, using teaching to end teaching.
What It Means for Practice
Sit. Don't try to become enlightened. Don't try to stop thinking. Don't try to be a good Buddhist. Just sit. The sitting itself is the Buddha-mind at work.