Further to
my post quoting from D. A. Carson yesterday, I thought I would add this excellent defense of the deity of Jesus from the pen of Wayne Grudem. The following is taken directly from his
Systematic Theology (Zondervan, 1994) pages 234-235. You can
purchase this helpful volume from Westminster Books here.
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The translation “the Word was God” has been challenged by the Jehovah’s Witnesses, who translate it “the Word was a god,” implying that the Word was simply a heavenly being but not fully divine. They justify this translation by pointing to the fact that the definite article (Gk. ho, “the”) does not occur before the Greek word theos (“God”). They say therefore that theos should be translated “a god.” However, their interpretation has been followed by no recognized Greek scholar anywhere, for it is commonly known that the sentence follows a regular rule of Greek grammar, and the absence of the definite article merely indicates that “God” is the predicate rather than the subject of the sentence.’ (A recent publication by the Jehovah’s Witnesses now acknowledges the relevant grammatical rule but continues to affirm their position on John 1:1 nonetheless.)’
The inconsistency of the Jehovah’s Witnesses’ position can further be seen in their translation of the rest of the chapter. For various other grammatical reasons the word theos also lacks the definite article at other places in this chapter, such as verse 6 (“There was a man sent from God”), verse 12 (“power to become children of God”), verse 13 (“but of God”), and verse 18 (“No one has ever seen God”). If the Jehovah’s Witnesses were consistent with their argument about the absence of the definite article, they would have to translate all of these with the phrase “a god,” but they translate “God” in every case.
John 20:28 in its context is also a strong proof for the deity of Christ. Thomas had doubted the reports of the other disciples that they had seen Jesus raised from the dead, and he said he would not believe unless he could see the nail prints in Jesus’ hands and place his hand in his wounded side (John 20:25). Then Jesus appeared to the disciples when Thomas was with them. He said to Thomas, “Put your finger here, and see my hands; and put out your hand, and place it in my side; do not be faithless, but believing” (John 20:27). In response to this, we read, “Thomas answered him, ‘My Lord and my God!” (John 20:28). Here Thomas calls Jesus “my God.” The narrative shows that both John in writing his gospel and Jesus himself approve of what Thomas has said and encourage everyone who hears about Thomas to believe the same things that Thomas did. Jesus immediately responds to Thomas, “Have you believed because you have seen me? Blessed are those who have not seen and yet believe” (John 20:29). As far as John is concerned, this is the dramatic high point of the gospel, for he immediately tells the reader—in the very next verse—that this was the reason he wrote it:
Now Jesus did many other signs in the presence of the disciples, which are not written in this book; but these are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in his name. (John 20:30—31)
Jesus speaks of those who will not see him and will yet believe, and John immediately tells the reader that he recorded the events written in his gospel in order that they may believe in just this way, imitating Thomas in his confession of faith. In other words, the entire gospel is written to persuade people to imitate Thomas, who sincerely called Jesus “My Lord and my God.” Because this is set out by John as the purpose of his gospel, the sentence takes on added force.