From Buddhism's Sacred Scripture: The Sutra of the Lotus of the Wonderful Dharma, Chapter 1, Part 2 of 3

At that time the Bodhisattva Maitreya questioned Manjushri: Now the World-Honored One has manifested these miraculous signs. But what is the cause of these auspicious portents? At that time Manjushri said to the Bodhisattva and Mahasattva Maitreya and the other great men:“Good men, I suppose that the Buddha, the World-Honored One, wishes now to expound the great Dharma, to rain down the rain of the great Dharma, to blow the conch of the great Dharma, to beat the drum of the great Dharma, to elucidate the meaning of the great Dharma. Good men, in the past I have seen this auspicious portent among the Buddhas. They emitted a beam of light like this, and after that they expounded the great Dharma. Therefore we should know that now, when the present Buddha manifests the light, we will do likewise. He wishes to cause all living beings to hear and understand the Dharma, Which is difficult for all the world to believe. Therefore He has manifested this auspicious portent.”