10 And when he was alone, they that were about him with the twelve asked of him the parable. 11 And he said unto them, Unto you it is given to know the mystery of the kingdom of God: but unto them that are without, all these things are done in parables: 12 That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them. (Mark 4.10-12)
[Cf. Fowler, "a double audience, consisting of one party that hearing shall hear and shall not understand, and another party that, when more is meant than meets the ear, is aware both of that more and of the outsiders' incomprehension..." Matthew's gospel, which most scholars consider to be later than Mark, softens the "elitist" rhetoric – only a bit – in its version of this discourse:]
10 And the disciples came, and said unto him, Why speakest thou unto them in parables? 11 He answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given. 12 Who whosoever hath, to him shall be given, and he shall have more in abundance: but whosoever hath not, from him shall be taken away even that he hath. [And here's the key revision:] 13 Therefore speak I to them in parables: because they seeing see not; and hearing they hear not, neither do they understand. (Matt. 13.10-14, my emphases)
The shift from "That seeing they may see, and not perceive..." to "Because they seeing see not..." shifts the "blame," as it were, for the incomprehensibility of Jesus' parabolic irony from Jesus himself (who in Mark teaches in parables precisely to exclude a particular audience) to his audience, which (in Matthew) is treated to parables because they have already somehow proved their obtuseness.
All this treated with depth and subtlety in Frank Kermode's The Genesis of Secrecy, and a thousand theological texts. But striking that Fowler finds a handy foundational text for the ironical moment (which he quotes but doesn't cite) in scripture, & in a bit of scripture which emphasizes the exclusivity of Jesus' discourse, its function of election and reprobation among listeners.
"Finally, there is the irony of irony. Generally speaking, the most fundamental irony of irony probably is that even it becomes tiresome if we are always being confronted with it. But what we want this irony to mean in the first place is something that happens in more ways than one. For example, if one speaks of irony without using it, as I have just done; if one speaks of irony ironically without in the process being aware of having fallen into a far more noticeable irony; if one can't disentangle oneself from irony anymore, as seems to be happening in this essay on incomprehensibility; if irony turns into a mannerism and becomes, as it were, ironical about the author; if one has promised to be ironical for some useless book without having first checked one's supply and then having to produce it against one's will, like an actor full of aches and pains; and if irony runs wild and can't be controlled any longer." (Frierich Schlegel, On Incomprehensibility, 1800)