佛說觀佛三昧海經 1.57

1.57

佛告父王：「佛涅槃後四部之眾，其欲觀菩薩為童子時及納妃時白毫相者，當作是觀。如此觀者是名正觀，若異觀者是名邪觀。」

The Buddha said to his father the king: "After the Buddha's nirvāṇa, among the fourfold assembly, those who wish to contemplate the mark of the white curl when the Bodhisattva was a boy and when he took a consort should contemplate in this way. Contemplating in this way is called correct contemplation; contemplating otherwise is called false contemplation."