Commentary Par XIX 88-90

All that is just in the world accords with God's will; on the other hand, no created good draws God's will to itself; its goodness is the manifestation of that will, not its cause.  Scartazzini/Vandelli (DDP Vandelli.Par.XIX.88-90) point to Dante's similar phrasing in Monarchia (Mon.II.ii.5), a passage that, in turn, may reflect the concept of God's inability to be unjust in Romans 9:14-15.

Having set himself up as a 'liberal' on the question of the eternal punishment of virtuous pagans, Dante now embraces the 'conservative' position, which has it that pagans are justly damned for not having intuited the truth of Christ.  He will play this hand out again in the next canto, where he will see saved pagans (their presence in Heaven surely reflects a 'liberal' mind-set), but will contrive to convince us (and himself?) that they had somehow found Christ.  As we will see, moral perfection alone will not procure the most just among pagans a place in Heaven, this poet's Christian pantheon.