大毘盧遮那成佛經疏 3.47

3.47

As for the verse saying:
'Mountain forests with many flowers and fruits,
Pleasing and pure springs,
Praised by all Buddhas,
For undertaking the round altar's rites':
Among all superior sites, mountain forests are the foremost. Even if multiple tiers of numerous peaks are dignified and secluded, if they lack flowers, fruits, and flowing springs, people will not delight in them. Then many conditions are lacking, and the place is also unsuitable. Therefore, there must be various renowned flowers and sweet fruits, accompanied by clear and pure springs and pools—a place pleasing to the mind. Such is praised by the Buddhas, and one may perform the rites of the maṇḍala there. Or, the practitioner in samādhi sees such a superior site, or hears the Holy Honoured One proclaim it, bidding them to make it there. The text below is also by this precedent. Furthermore, 'mountain' is called nāga in Sanskrit, meaning immovable. This means that the ācārya, in yoga, observes that this practitioner abides within the fourfold inherent nature of phenomena and that their performed wholesome deeds are firm and unshakeable of mind—namely, reverently serving teachers and elders, filially providing for parents, and so forth. Wherever the flowers and fruits of the eight minds burgeon and can generate pure dharmas, there one may establish the maṇḍala. Furthermore, when the pure bodhicitta rests securely in the real truth, firm and unshakeable, unable to be stirred by the great winds of the eight directions, with the flowers and fruits of mahākaruṇā and upāya pervading everywhere, constantly flowing with pure dharmas to benefit and gladden sentient beings—this is what is most praised by the Buddhas, a fine site to construct a maṇḍala.