The “Jesus-is-God,” i.e., Yahweh argument: ‘Isaiah said these things because he saw Jesus’ glory as God [YHWH] in a pre-incarnate state.’
What John actually describes:
‘Isaiah said these things [John 12.38 citing Isa. 53:1; 10.40 citing 6:10 & NOT 6.1, 3!] because he saw the Messiah’s glory and spoke of him.’
This is a prominent theme of the prophet about “the Servant of YHWH,” not Jesus “in a pre-incarnate state”!
In other words, the prophet refers to Messiah’s FUTURE “glory”:
Isa. 4.2: “In that day the branch of YHWH shall be beautiful & glorious…”
Isa. 49.5 LXX: “And now, thus says the Lord that formed me from the womb to be his own servant, to gather Jacob to him and Israel. I shall be gathered & glorified before the Lord, and my God shall be my strength.”
Isa. 52.13-15 LXX: “Behold, my servant shall understand, and be exalted, and greatly glorified. You will amaze many…and your glory shall not be honored by the sons of men [people]. Thus shall many nations wonder at him; & kings shall keep their mouths shut: for they to whom no report was brought concerning him, shall see; & they who have not heard, shall consider.”
Williams, Isaiah in the New Testament, pp. 112-113.
“[John 12.41 need not] relate solely to the quotation drawn from Isa. 6:10….The prophetic testimony presented by Isaiah (53:1; 6:10) reflects his vision of Jesus’ earthly glory, which enabled him to speak as he did about Jesus’ earthly mission & to predict the unbelief that Jesus would encounter during his earthly life.” Compare: Isa. 9:6-7; 11:1-10; 16:5; 32:1; 33:17; 42:1-4; 52:13-15; 61:1-3.
Again, the prophet never identifies the Messiah as God but as the Servant, aka Messiah of God:
* “the branch of Jehovah” (4:2),
* “chosen one, in whom [God’s] soul delights,” “servant” (42:1; 49.1-7; 52:13),
* “grew up before YHWH like a young plant” (53:2),
* “the suffering servant” (53:6)
But even if John 12.41 had cited Isa. 6.1, 3, the glory of God is the glory of His Messiah!
Matt. 16.27: “For the Son of Man will come with his angels in the glory of his Father & will judge all people according to their deeds.”
Matt. 25.31: “When the Son of Man comes in his glory, and all the angels with him, then he will sit on his glorious throne.”
Lastly, Isaiah is among the prophets who “saw” Messiah’s glory according to 1 Peter 1.10-12:
“Concerning this salvation, the prophets sought and searched diligently, who prophesied of the grace that would come to you, investigating for whom or what time the spirit of Messiah, which was in them, pointed to, when it predicted the sufferings of Messiah, & the glories that would follow them.” Cp. Abraham “rejoiced to see my day”, John 8.56.