Tulku Urgyen Rinpoche on "one mind"

At present the state of ordinary people is like pure gold covered with dirt. Our buddha nature is covered by temporary obscurations. One of the main veils that needs to be purified is our fixation on duality, on solid reality. Once it is purified then gold is just pure gold. As long as our mind is confused, bewildered, deluded, and mis­taken, our buddha nature continues to be dragged through the realms of samsara. But when the mind is unconfused, unmistaken, and undeluded, it is the bud­dha nature itself. It is not that the buddha nature is one thing and our mind is another separate thing. They are not two different entities. The undeluded mind itself is the pure gold, the buddha nature. Sentient beings do not have two minds. When the mind is deluded it is given the name ‘sentient being.’ When the mind is undeluded, unmistaken, it is known as buddha.
It is said that “there is no buddha apart from your own mind.” We do not have two minds. There is just one mind which is either deluded or undeluded. The buddha nature is exactly the originally unmistaken qual­ity of our mind, also known as Samantabhadra, the dharmakaya buddha.
--from Repeating the Words of the Buddha