The WT organization’s interpretation of what is the main theme of the Bible is the following:
“The main theme of the Bible is that Jehovah’s name will be vindicated as he fulfills his purpose for the earth by means of his Kingdom under Christ.”
(Paragraph 8, https://www.jw.org/finder?srcid=jwlshare&wtlocale=E&prefer=lang&docid=2023605 )
Is that really the main theme of the Bible?
Or what does the Bible say ?
God himself gives the first prophecy after sin came into the world as a foundation for what the Bible is about:
Genesis 3:15 And I will put enmity between you and the woman and between your offspring and her offspring. He will crush your head, and you will strike him in the heel.”
Who would become the offspring that nullifies Satan's deeds?
Colossians 2:2 “the sacred secret of God, namely, Christ.”
1 Corinthians 15:20 But now Christ has been raised from the dead, the firstfruits of those who have fallen asleep in death. 21 For since death came through a man, resurrection of the dead also comes through a man. 22 For just as in Adam all are dying, so also in the Christ all will be made alive. 23 But each one in his own proper order: Christ the firstfruits, afterward those who belong to the Christ during his presence. 24 Next, the end, when he hands over the Kingdom to his God and Father, when he has brought to nothing all government and all authority and power. 25 For he must rule as king until God has put all enemies under his feet. 26 And the last enemy, death, is to be brought to nothing. 27 For God “subjected all things under his feet.” But when he says that ‘all things have been subjected,’ it is evident that this does not include the One who subjected all things to him. 28 But when all things will have been subjected to him, then the Son himself will also subject himself to the One who subjected all things to him, that God may be all things to everyone.