"If one wishes to see the Buddha, then one sees him. If one sees him, then one asks questions. If one asks, then one is answered, he hears the sutras and rejoices greatly. He reflects thus: “Where did the Buddha come from? Where did I go to?” and thinks to himself: “The Buddha came from nowhere, and I also went nowhere.” He thinks to himself:
The three realms—the realm of desire, the realm of form, and the formless realm—these three realms are simply made by thought. Whatever I think, that I see. The mind creates the Buddha. The mind itself sees him. The mind is the Buddha. The mind is the Tathāgata. The mind is my body, the mind sees the Buddha. The mind does not itself know the mind, the mind does not itself see the mind. A mind with conceptions is stupidity, a mind without conceptions is nirvana. There is nothing in these dharmas that can be enjoyed; they are all made by thinking. If thinking is nothing but empty, then anything that is thought is also utterly nonexistent."
(Pratyutpanna Samadhi Sutra, ch 2, BDK ed, p 26)