佛說處處經 1.6

1.6

「佛得頂中光明者，有三因緣：一者、然燈施佛寺；二者、愛樂明經；三者、解人疑結。

"That the Buddha attained the radiance from the crown of his head is due to three nidānas: first, lighting lamps to give to Buddhist temples; second, delighting in the illuminating sūtras; third, resolving people's doubts and fetters.