"These things" that John speaks of above pertain to two different chapters of Isaiah as quoted by John: Isaiah 6 and Isaiah 53. Thus the time being spoken of when Isaiah saw the glory of Yahweh in Jesus covers all the time recorded at least from Isaiah chapter 6 to Isaiah chapter 53.

According to many, there is "clear" proof that Jesus is Yahweh in John's statements as recorded in John 12:37-41. In actuality If John's intent was to show that Jesus is Yahweh, he certainly did it in a very vague and obscure manner. However, there is no indication that this was John's intent. His intent was to show how Yahweh had prophesied through Isaiah concerning the blindness of Israel as a whole repecting the arm of Yahweh. The "arm of Yahweh" represents Yahweh's power and rulership. -- Psalm 10:15; Ezekiel 30:21; Jeremiah 48:25.

As noted, John quotes from two different chapters of Isaiah: chapters 6 aand 53. Verse 40 is indirectly derived from Isaiah 6:10. John refers to this to show why the Jews cannot believe in Jesus -- by whom the arm of Yahweh is made known. It is because Yahweh has concealed the truth from them. Verse 41, then refers back to Isaiah 6:10 [not Isaiah 53:1], in the context of which Isaiah had seen the glory of Yahweh. In Isaiah 6:8, it is Isaiah that says: "Here I am, send me!", to Adonai when asked who will go to tell the people concerning "us". -- that is, Adonai and all the in the temple glory just seen by Isaiah.

There is some difference of opinion as to whether Adonai in Isaiah 6:1,8 refers to Jesus or Yahweh. For the present, we will assume that they do refer to Yahweh. Thus Isaiah says he will speak of Yahweh to the people, which would correspond to the John's last remark in John 12:41, "and he [Yahweh] spoke of him [Jesus]." After which Yahweh lets Isaiah know that the people will hear, but not understand, and in effect says the he [Yahweh] has blinded them, etc., which is the verse referenced indirectly in John 12:40. In view of this, it could have been that John was referring back to the God of Jesus, Yahweh, mentioned in John 12:38 as well as in the one who did the blinding in John 12:40. Thus "his glory" spoken of in John 12:42 would be the glory of Yahweh that Isaiah saw, and not the glory of Jesus at all.

We might add that many individuals did believe in Jesus, as John states in John 12:42. However, The present evil world is not the time when Jesus and his saints are revealed to all -- only a few believe. Their revealing to the world will be in the next age -- while Satan is abyssed, for which time the world is ignorantly waiting for. (Romans 8:19-22; Revelation 20:1-3; Isaiah 2:2-4; 11:9; 25:7) Thus in this present age, the world is still blinded by Satan's deceptions. -- 2 Corinthians 4:4; Revelation 12:9.

Nevertheless, it is possible that John did mean that Isaiah had seen the glory of Jesus. From this viewpoint we need to note in the Isaiah scene, verse one does not have the Hebrew tetragrammaton for Yahweh, but "the Lord" sitting on the throne. Some translations put Yahweh here, but the Great Isaiah Scroll (Dead Sea Scroll) does not have Yahweh here*, but rather adonai (or adoni). The scribes who added the vowel points to try to distinguish adonai and adoni did so many centuries after Jesus was on earth. They added the vowel point in each place where they believed the text referred to Yahweh, but their work is not infallible, so it is possible that their addition of the vowel point in Isaiah 6:1 is actually an error on their part. Thus, we conclude that Isaiah actually referred to "my Lord", regarding the coming Messiah, as did David in Psalm 110:1. Now it is declared that "No one has seen God at any time. The only begotten Son, F6 who is in the bosom of the Father, He has declared Him." (John 1:18, New King James Version. We should then understand that Isaiah saw the glory of God "in the face of Jesus Christ," who is "the brightness of the Father’s glory and the express image of his person." (See 2 Corinthians 4:6) In Isaiah 6:8 also it is Adonai (or adoni, my Lord, the Lord Jesus) who gives the message and pronounces the judgment. Therefore. we believe that adonai as it appears in the Masoretic text of Isaiah 6:1,8 should actually be adoni, referring to Isaiah's Lord (as David refers to "my Lord" in Psalm 110:1), that is, Jesus.
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*The Great Isaiah Scroll supports that the word rendered "Lord" in Isaiah 6:1,8 is not Yahweh, but that it was originally Adonai (High Lord), or Adoni (my Lord).
http://reslight.net/adonay134.html

The holy spirit reveals through the scriptures that Jesus receives his inheritance and dominion (power) from Yahweh. His power and authority is given to him by his God, his Supreme Being. Jesus is not Yahweh [his God and Father] who gives him this dominion, all authority and power (with the evident exception of God himself -- 1 Corinthians 15:27), yet the exercise of this power and authority by Jesus is all to the praise of Yahweh, the God and Father of the Lord Jesus. The Bible writers never claimed that Jesus is the ultimate "source" of his own power. -- Psalm 2:6-8; 45:7; 110:1,2; Isaiah 9:6,7; 11:2; 42:1; 61:1-3; Jeremiah 23:5; Daniel 7:13,14; Matthew 12:28; 28:28; Luke 1:32; 4:14,18; 5:17; John 3:34; 5:19,27,30; 10:18,36-38; Acts 2:22; 10:38; Romans 1:1-4; 1 Corinthians 15:27; 2 Corinthians 13:4; Colossians 1:15,16; 2:10; Ephesians 1:17-22; Philippians 2:9-11; Hebrews 1:2,4,6,9; 1 Peter 3:22.

Additionally, Jesus reflects the glory of God, thus Yahweh's glory was being seen in Jesus as the representative of Yahweh. As Jesus performed his miracles, the glory of Yahweh was being seen in Jesus. (Matthew 9:8; Matthew 15:31; Mark 2:12; Luke 5:26; 7:16; 13:13; 23:47; John 11:40; 13:31,32) All will bow to Jesus to the glory of God. (Philippians 2:11) It is the glory of Yahweh that will be revealed through Jesus and the church during the Millennial rule. - Psalm 2:6; Isaiah 11:9; 9:6,7; 60:2; John 11:40; 13:31; Revelation 21:10,11.

At any rate, the reference in John 21:41 certainly does not identify Jesus as being Yahweh, as is taught by many trinity believers, as well as some others who wish to believe that Jesus is Yahweh.

See: Understanding Kingdom Mysteries
and
The Restoration of All Things

Updated: April 19, 2005.