In the Sutra of Innumerable Meanings, the first chapter is my favorite. First is the description of how Bodhisattvas turn the wheel of the Dharma:

They are able, moreover, to clearly perceive conditioned desires of the senses. By means of Dharma-grasping empowerments (dhāraṇīs), and with unlimited facility of eloquence, they call upon the Buddha to turn a wheel of the Dharma; emulating him, they are able to turn it as well. They first bring it down in tiny drops that dissolve the dirt of delusive passions. They open nirvana’s gates and fan winds of emancipation—dispelling the world’s fevers and trials with the cool refreshment of the Dharma. Next, raining down the deeply profound twelve-linked chain of dependent origination (pratītyasamutpāda), they drench the intense solar fires of assembled sufferings of ignorance, illness, aging, and death. Then, pouring the supreme Great Vehicle to overflowing, they immerse and soak the various roots of goodness that living beings possess, cast seeds of goodness widely over fields of beneficial effects, and inspire all beings everywhere to germinate the sprout of enlightenment.

But more important is the revelation of our role – the role of those who are suffering – in encouraging the Buddha to return and teach after his attainment of enlightenment:

Great One! Most Venerable Fully Awakened Master!
You are without stain, contamination, or attachment!
Nurturer of human and heavenly beings!
Tamer of elephants and horses!
You infuse the fragrance of virtue into all things by means of the winds of the Way!
You are serene in wisdom, calm in emotion, composed in deep reflection,
And—volition extinguished, discriminations set aside—likewise tranquil in mind.
You have forever cast away delusive ideas, reflections, and thoughts—
No more to become entangled in all the facets of existence.
What you embody is not existing, and yet not nonexistent;
Is neither direct nor indirect cause; has no sense of self or other;
Is neither square nor round; is not brief or long;
Neither appears nor disappears; is without origination or cessation;
Is neither created nor self-arisen, nor is it produced;
Neither sits nor lies down; does not walk or stand; Neither moves nor turns; is not static or idle;
Neither advances nor retreats; is not imperiled or secure;
Neither is, nor is not; has no gain or loss;
Is neither here nor there; does not come or go;
Is neither blue nor yellow; is not red or white;
Is not crimson, is not purple or multicolored;
Comes forth from the perfection of behavioral principles, concentration, discernment, emancipation, and perspective that pertains to emancipation;
Rises from three kinds of transcendent knowledge, the six transcendent powers, and the avenues to enlightenment;
Emanates from kindness, compassion, ten capabilities, and dauntlessness;
And emerges according to the good karmic actions of living beings.

I was deeply disappointed with Rissho Kōsei-kai’s “modern” translation of this sutra, which changed that last line to read:

And he comes forth as a result of his good karma as a living being.”

I wrote about this two years ago. What brings this up now is something I read in “The History of Buddhism in India and Tibet,” which was written by the 14th century Tibetan scholar Bu-ston and translated into English by Eugene Obermiller in 1932.

Now, (in reality) the Lord, having extirpated the force which calls forth speech, has attained Enlightenment in perfect silence and then, up to the time of his attaining Nirvāṇa, has not uttered a single word. But, in accordance with the thoughts (and the needs) of the living beings, he appears as if teaching (the Doctrine) in various forms, as it is said:

A cymbal on a magic circle
Issues its sounds, being agitated by the wind,
And although there is nothing with which it is beaten,
Its sound is nevertheless heard.
Similar is the voice of the Buddha which arises,
Being called forth by the thoughts of the living beings,
And owing to their previous virtuous deeds.
But the Buddha (himself) has no constructive thought
(By which his words could be conditioned).

The voice of the Buddha is therefore something inconceivable for our mind.

The Teacher has thus perceived the living beings subjected to suffering, being obscured by the pellicule of ignorance, tied by the knot of egocentristic views, suppressed by the mountain of pride, consumed by the fire of desire, wounded by the weapons of hatred, cast into the wilderness of Saṃsāra, and unable to cross the streams of birth, old age, illness, and death. And, in order to deliver them (from this suffering), from between his teeth resembling a beautiful sonant conch-shell, he stretched forth his tongue endowed with miraculous power, ejected his voice, similar to that of Brahma, and thus expounded the whole of the Doctrine.

Putting the two descriptions together: The Buddha emerges according to the good karmic actions of living beings, being called forth by the thoughts of the living beings and owing to their previous virtuous deeds.