大毘盧遮那成佛經疏 10.8

10.8

時彌勒菩薩住於普遍大慈發生三昧自心說者，普謂平等，遍滿一切法界也。稱於法界而生大慈，能遍與一切眾生正法之樂，是彼所入門也。如其自所進達，入于三昧而說真言，故言自心說也。說義亦如上。

At that time Bodhisattva Maitreya, abiding in the samādhi of generating universal great maitrī, spoke from his own mind: "Universal" means equal, completely pervading all dharmadhātu. Generating great maitrī commensurate with the dharmadhātu, he can universally bestow the bliss of the true Dharma upon all sentient beings; this is the gateway he has entered. In accordance with what he has personally advanced to and penetrated, entering samādhi he spoke the mantra; hence it says "spoke from his own mind." The meaning of the exposition is also as above.