Luke 8:10

But our Lord told them the reason why He spake to the multitudes in parables, as follows, And he said, Unto you it is given to know the mysteries of God.

(ubi sup.) When you hear this you must not entertain the notion of different natures, as certain heretics do, who think that some men indeed are of a perishing nature, others of a saving nature, but that some are so constituted that their will leads them to better or worse. But add to the words, To you it is given, if willing and truly worthy.

Rightly then do they hear in parables, who having closed the senses of their heart, care not to know the truth, forgetful of what the Lord told them. He that hath ears to hear, let him hear. Who in truth deign to receive the word which they hear with no faith, with no understanding, at least with no attempt to test the value of it.

But to those who are unworthy of such mysteries, they are obscurely spoken. Hence it follows, But to the rest in parables, that seeing they might not see, and hearing they might not understand. For they think they see, but see not, and hear indeed, but do not understand. For this reason Christ hides this from them, lest they should beget a greater prejudice against them, if after they had known the mysteries of Christ, they despised them. For he who understands and afterwards despises, shall be more severely punished.