金剛三昧經論 2.136

2.136

經曰　佛言：「如是。眾生之心實無別境。何以故？心本淨故、理無穢故。以染塵故名為三界，三界之心名為別境，是境虛妄從心化生；心若無妄即無別境。」

The sūtra says: The Buddha said, 'It is so. The minds of sentient beings truly have no distinct objective realm. Why is this? Because the mind is originally pure, and the principle is free from defilement. It is on account of defiling dusts that they are named the "three realms," and the mind of the three realms is named a "distinct objective realm." These objective realms are illusory, created and arisen from the mind; if the mind is without delusion, there is no distinct objective realm.'