大毘盧遮那成佛經疏 1.28

1.28

The sūtra says: 'Why is that? That whose nature is identical with space is identical with the mind; that whose nature is identical with the mind is identical with bodhi. Thus, Master of Secrets, the mind, the realm of space, and bodhi: these three are non-dual. Having compassion as their root, they are fulfilled by the upāyapāramitā.' As with the various entries into the gateways of purity above, all are meant to elucidate the meaning of one's own mind seeking bodhi. Here it concludes by stating that space without defilement is itself the mind, and the mind is itself bodhi; in essence they are originally of one mark, yet have three names. This single dharmadhātu mind, although ultimately unborn through causes and conditions, does not destroy the dharmatā of causes and conditions. Because it is unborn, there is no distinction between subject and object; because it is indestructible, it also takes compassion as its root and is fulfilled by the upāyapāramitā, which is precisely the ultimate, inconceivable meaning of the middle way.