The character of the Wicked One becomes clearer in this verse, which is full of echoes from the Old Testament (Daniel 11.36; Ezekiel 28.2, cf. vv. 6, 9; Isaiah 14.13-14). Paul is probably also influenced by the tradition later recorded in Mark 13.14 and Matthew 24.15. Jews had vivid memories of the desecration of the Temple in Jerusalem by Greek invaders in 168 B.C., and Paul’s language here is therefore heavy with emotive associations which the translator must try to convey—if possible in his text, otherwise by a note. Moffatt adds “actually” for emphasis before “seating himself in the temple of God.” Die Bibel im heutigen Deutsch produces a similar effect by beginning a new sentence with “yes, he will set up his throne in God’s temple.”
He will oppose may be rendered as “he will speak against,” “he will denounce,” or “he will regard as nothing.”
To oppose every so-called god or object of worship could be interpreted as being a valid and righteous thing for the Wicked One to do, since he would be denouncing all kinds of idols and fetishes. Since this is not what is meant, a more satisfactory rendering may be “every supernatural being which men worship,” or “every spirit or god which men worship.”
He … will put himself above them all must not be translated in a strictly literal sense of spatial position. What is mean here is that the Wicked One will consider himself to be superior to all supernatural powers or beings. Therefore one may wish to translate “he will consider himself greater than any of these,” or “he will assert that he is more powerful than any spirit or god.”
Some Greek manuscripts, followed by King James Version, add “as God” before sit down in God’s Temple, but this addition is not found in the best manuscripts.
And claim to be God is literally “claiming” or “proclaiming himself that he is God.” King James Version‘s “shewing himself that he is God” is too weak. These words may either (1) express the purpose for which, or the reason why, the Wicked One sits down in God’s Temple (cf. Phillips “to show that he really claims to be God”), or (2), more probably, explain and partly repeat what Paul has said earlier in the verse. Claim to be God may be translated as “announce that he is God” or “tell the people, I am God himself,” or “… I myself am God.”
Quoted with permission from Ellingworth, Paul and Nida, Eugene A. A Handbook on Paul’s Second Letter to the Thessalonians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .