Avatamsaka Sutra: Volume 39. Book 26: The Ten Stages, the 6th section
(Taisho Tripitaka 0279)
At that time, all Buddhas of the ten directions will emit from their glabellas (the location between the eyebrows) pure rays of light, which are called The Supernatural Power That Enhances The Universal Wisdom. These rays of light, together with countless accompanying lights, will universally illuminate all worlds of the ten directions, circulate them clockwise ten times, reveal the immense omnipotence of the Tathagatas, enlighten innumerable hundreds of thousands of billions of nayutas of Bodhisattvas, universally shake all Buddha-Worlds, eliminate all evil paths' sufferings, block out all demons' palaces, show all the places in which the Buddhas achieve Bodhi, and show the congregations, sublimities, and majesties of those Bodhimandas.
In such a way, having filled the whole universe, permeated the whole Dharma-Realm, and illuminated all the worlds, these lights will come to this Bodhisattva Congregation, circulate it clockwise, and manifest myriad sublime things. Having done these, these lights will enter the great Bodhisattva's body through the summit of his head, and their accompanying lights will enter into those accompanying Bodhisattvas' heads. At that time, this Bodhisattva will gain millions of Samadhis that he has never gained before, and then it is known that he Has Gained The Conferment, Has Entered the Buddhas' Realm, Has All The Ten Powers, and Is Counted As A Buddha.
For example, with the only exception of the great ocean, a great rain showered by the dragon king Sagara, can not be placed, accepted, contained, or kept within any place. Likewise, with the only exception of the Bodhisattvas of the tenth stage, the Thus Come Ones' secret treasury --- the great Dharma light, the great Dharma illumination, and the great Dharma rain, can not be placed, accepted, contained, or kept within any living being even if he is a Voice Hearer, Solitary Awakener (pratyeka-buddha), or a Bodhisattva of the ninth stage.
Child of the Buddha, for example, the great ocean can embrace, accept, contain, and keep a great rain showered by one great dragon king; moreover, if two, three, or even countless dragon kings, within a moment as short as a flash thought, shower down countless rains simultaneously, the great ocean can also embrace, accept, contain, and keep them. Why? Because it is a boundless and vast vessel. Likewise, a Bodhisattva dwelling in Dharma Cloud stage, can embrace, accept, contain, and keep one Buddha's Dharma light, Dharma illumination, and Dharma rain; furthermore, if two, three, or even countless Buddhas preach simultaneously within a moment as short as a flash thought, this Bodhisattva can also accept them. Therefore, this stage is called Dharma Cloud.