俱舍論疏 23.85

23.85

論「若得頂法至不斷善根」，此第二明頂勝利。言「而增」者，後必兼前。《正理論》加觀察三寶殊勝功德為門，引生淨信心故。若得頂已不斷善根，如何經說天授退頂？由彼曾起近頂善根，依未得退，密作是說。

On the Śāstra's statement: "If one attains the dharma of Summits [...] one does not sever the roots of goodness": this second [section] clarifies the superior benefit of Summits. Saying "yet increases" means that the latter definitely incorporates the former. The Nyāyānusāra adds contemplation of the superior virtues of the Three Jewels as an entry gate, because it induces pure faith. If having attained Summits one never severs the roots of goodness, why does the sūtra say that Devadatta retrogressed from Summits? Because he had once given rise to the roots of goodness close to Summits, this was spoken esoterically in terms of his retrogression before attainment.