Visuddhimagga XVII-33

 583. Kasmā panevaṃ desetīti? Paṭiccasamuppādassa samantabhaddakattā sayañca desanāvilāsappattattā. Samantabhaddako hi paṭiccasamuppādo, tato tato ñāyapaṭivedhāya saṃvattatiyeva. Desanāvilāsappatto ca bhagavā catuvesārajjapaṭisambhidāyogena catubbidhagambhīrabhāvappattiyā ca. So desanāvilāsappattattā nānānayeheva dhammaṃ deseti.

为什么他要这样说？因为缘起的完善及他（世尊）自己到达说法的微妙之故。即缘起的确是完善的，由（四种说法的）任何一种都得通达正道。因为世尊以无畏及四无碍相应并到达四种甚深的状态，故为到达说法的微妙，因他到达说法的微妙，所以才能以种种的方法而说法。

Ñ(XVII,33): Why does he teach it thus? Because the dependent origination is wholly beneficial and because he has himself acquired elegance in instructing. For the dependent origination is entirely beneficial: starting from any one of the four starting points, it leads only to the penetration of the proper way. And the Blessed One has acquired elegance in instructing: it is because he has done so through possession of the four kinds of perfect confidence and the four discriminations and by achieving the fourfold profundity (§304) that he teaches the Dhamma by various methods.