Is it John or Jesus quoting Isaiah in John 12:38 & 40?

Question

Jesus is not attributed to be speaking in either John 12:38 or 40 according to a "red letter" edition.

However, regarding verse 38 Ellicott's Commentary for English Readers states:

Lord, who hath believed our report? The quotation is from the Greek version of Isaiah 53:1. That prophecy was by all understood of the Messiah. The prophet’s lamentation of the neglect of the prophetic message by the people is here placed by the Evangelist, in his interpretation of it, in the lips of the Messiah Himself, as He, in the fuller meaning, addresses the Father with the words, "Who hath believed our report?"...

Also, in regards to verse 38, Meyer's NT Commentary states:

The passage is Isaiah 53:1, closely following the LXX. The lament of the prophet over the unbelief of his time towards his preaching (and that of his fellows, ἡμῶν), and towards the mighty working of God announced by him, has, according to the Messianic character of the whole grand oracle, its reference and fulfilment in the unbelief of the Jews towards Jesus; so that in the sense of this fulfilment, the speaking subject (addressing God, κύριε, comp. Matthew 27:46), which Isaiah introduces, is Jesus, not the evangelist and those of like mind with him (Luthardt).

Regarding verse 40, the commentary indicates that John's quotation is Jesus first person: Bengel's Gnomen

John 12:40. Τετύφλωκεν, hath blinded) God, by a just judgment on them. There follows, with a change of person, I the Messiah should heal them.—πεπώρωκεν)

Also, regarding verse 40, since Jesus connects the fulfillment of this prophecy in Matthew 13:14, could it be inferred that John (as others do) are reciting what Jesus has already acknowledged and the attribution should be to Jesus? Ellicott's Commentary for English Readers

He hath blinded their eyes, and hardened their heart. . . .—These words are quoted three times in the New Testament. Our Lord, as we have seen, quotes them as explaining His own teaching (Matthew 13:14); St. John quotes them here to explain the rejection of that teaching;

[emphasis added]

Answer 1

John Chrystostom's Homily (delivered in Greek to Greeks) on this passage maintains that John, and not Jesus, was expressing the prophesy in the verses referenced (Homily LXVIII on the Gospel According to John). For example:

“They could not believe,” it saith, “because that Esaias said, Ye shall hear with your ears, and not understand. These things he said, when he saw His glory, and spake of Him.” Here again observe, that the “because,” and “spake,” refer not to the cause of their unbelief, but to the event. For it was not “because” Isaiah spake, that they believed not; but because they were not about to believe, that he spake. Why then doth not the Evangelist express it so, instead of making the unbelief proceed from the prophecy, not the prophecy from the unbelief? And farther on he putteth this very thing more positively, saying ...

Regarding John 12:38, what appears in the Greek Gospel and in the Septuagint are identical:

John 12:38

Κύριε τίς ἐπίστευσεν τῇ ἀκοῇ ἡμῶν καὶ ὁ βραχίων κυρίου τίνι ἀπεκαλύφθη

Isaiah 53:1 LXX

κύριε, τίς ἐπίστευσεν τῇ ἀκοῇ ἡμῶν καὶ ὁ βραχίων κυρίου τίνι ἀπεκαλύφθη

That is (KJV),

Lord, who hath believed our report?
and to whom hath the arm of the Lord been revealed?

Verse 40, on the other hand, is a paraphrase:

John 12:40 (with KJV trans.)

Τετύφλωκεν αὐτῶν τοὺς ὀφθαλμούς
καὶ πεπώρωκεν αὐτῶν τὴν καρδίαν
ἵνα μὴ ἴδωσιν τοῖς ὀφθαλμοῖς
καὶ νοήσωσιν τῇ καρδίᾳ
καὶ ἐπιστραφῶσιν
καὶ ἰάσωμαι αὐτούς

He hath blinded their eyes,
and hardened their heart;
that they should not see with their eyes,
nor understand with their heart,
and be converted,
and I should heal them.

Isaiah 6:10 LXX (with Brenton trans.)

ἐπαχύνθη γὰρ ἡ καρδία τοῦ λαοῦ τούτου
καὶ τοῖς ὠσὶν αὐτῶν βαρέως ἤκουσαν
καὶ τοὺς ὀφθαλμοὺς αὐτῶν ἐκάμμυσαν
μήποτε ἴδωσιν τοῖς ὀφθαλμοῖς
καὶ τοῖς ὠσὶν ἀκούσωσιν
καὶ τῇ καρδίᾳ συνῶσιν
καὶ ἐπιστρέψωσιν
καὶ ἰάσομαι αὐτούς

For the heart of this people has become gross,
and their ears are dull of hearing,
and their eyes have they closed;
lest they should see with their eyes,
and hear with their ears,
and understand with their heart,
and be converted,
and I should heal them.

The latter day commentators seem to maintain that because Jesus was (presumably) present, the words written down by John must have necessarily been spoken by Jesus, since He is God and since the words were originally given to Isaiah by God.

Bengel seems to have been wrestling with the contradiction between the Septuagint version of Isaiah 6:10 and the version in the Masoretic Text, which reads:

Isaiah 6:10 (Masoretic Text - KJV 1900)

Make the heart of this people fat,
And make their ears heavy, and shut their eyes;
Lest they see with their eyes, and hear with their ears,
And understand with their heart, and convert, and be healed.

He reasons that since the prophesy in John reads "I will heal them" (1st person) and the "original" prophesy read "Lest they ... be healed" (3rd person), it must be Jesus who is speaking. But this interpretation overlooks that the phrase appears in the first person in the Septuagint version.

Answer 2

There is a grammatical pause in John’s Gospel narrative (v37-43), where the Evangelist inserts his commentary on Isaiah.

Page 250 of Chrysostom’s Homily (provided by @the-nontheologin in the marked answer) provides an intriguing description of Jesus’s discourse

He beginneth with humble and modest expressions [then raising His tone, Jesus] retireth; then He cometh to them again...with words of humility,`

Prompting a rhetorical inquiry of the text...

And where hath He done this?

The inquiry points to verse 12:44, where most English translations begin with a conjunctive adverb but|then|and; which necessitates a preceding-contrasting predicate/verb (and subject); which can only be located by back-tracking all the way to verse 36, forcing a split in the narrative, which is diagrammed below:

 <= verse 36  
  “When Jesus had said these things,
he went away and hid himself from them.” narrative
  Jesus quoted        
  (first preceding)
predicate and subject
 verses 37-43  [commentary on Isaiah]                                                                                    grammatical pause     
 >= verse 44  
  “But/Then/And Jesus shouted...”             
  narrative
  Jesus quoted        
  (connecting)
conjunctive adverb     

So grammatically, the commentary on Isaiah is not part of the narrative quotations of Jesus. Bookended by the narrative, the commentary looks as if it belongs to Jesus, however there is a distinct pause inserted by the author.

The only wrinkle in this observation is that the tell-tale conjunction but|then|and is not explicit in the Greek. So there is the assumption that the majority translations all make some linguistic inference.