佛說觀佛三昧海經 4.5

4.5

The Buddha told Ānanda: "If sentient beings wish to contemplate the light from Śākyamuni Buddha's uṣṇīṣa, they should make this contemplation. For one who makes this contemplation, even if their mind is dull, they will see it in dreams. Although it is a mental concept, it can eradicate immeasurable hundreds of thousands of heavy sins. One who contemplates like this will certainly see all the great bodhisattvas in their present life. Because they see the bodhisattvas, they will hear them expound the Dharma; because they hear the Dharma expounded, they will attain a dhāraṇī, and that dhāraṇī is called 'revolving memory retention.' Such contemplation is called right contemplation; if one contemplates otherwise, it is called wrong contemplation."