Dutiyasūriyūpamasutta
“Sūriyassa, bhikkhave, udayato etaṁ pubbaṅgamaṁ etaṁ pubbanimittaṁ, yadidaṁ—aruṇuggaṁ; evameva kho, bhikkhave, bhikkhuno sattannaṁ bojjhaṅgānaṁ uppādāya etaṁ pubbaṅgamaṁ etaṁ pubbanimittaṁ, yadidaṁ—yonisomanasikāro. Yonisomanasikārasampannassetaṁ, bhikkhave, bhikkhuno pāṭikaṅkhaṁ—satta bojjhaṅge bhāvessati, satta bojjhaṅge bahulīkarissati.
The Simile of the Sun (2nd)
“Mendicants, the dawn is the forerunner and harbinger of the sunrise. In the same way, for a mendicant rational application of mind is the forerunner and harbinger of the arising of the seven awakening factors. A mendicant accomplished in rational application of mind can expect to develop and cultivate the seven awakening factors.