佛說觀佛三昧海經 9.27

9.27

At that time, in order to entrust this matter, the Bhagavat stood in the sky with sovereign deportment, performed the eighteen transformations, displayed all lights, and addressed Ānanda, saying: "If there are sentient beings who wish to contemplate the Buddha, they should contemplate in this manner." When the Buddha spoke these words, one billion two hundred million sons of the gods attained the buddhānusmṛti-samādhi and received predictions in his presence.