Commentary Purg III 38-39

Some commentators (e.g., Benvenuto) are of the opinion that these lines indicate that had humankind been able to know the final mysteries, Adam and Eve would not have fallen and Christ would not have been needed to save us.  It seems far more likely that Dante's thought is more logically connected than such an analysis would indicate: had we known all, there would have been no need for Christ to come to bring us the final truth of things.  The focus here is not moral so much as it is intellectual.