The ESV translates 2 Thess 1:9, "They will suffer the punishment of eternal destruction, away from the presence of the Lord and from the glory of his might" The NIV and NRS likewise translate the first "away from" as "shut out" or "separated from", while maintaining the same translation for the second half of the verse.
These translations are unfortunate renderings of the Greek text, which consequently affects our view of hell and of God. 2 Thess. 1:3-12 is written to encourage the saints who are being persecuted and afflicted that God will certainly judge those who have afflicted them. The passage is meant to encourage Christians with a reminder of God's wrath, yet note how these translations dull the intended teaching and effect.
(1) V. 6 & 8 explicitly state an active punishment from the Lord, versus a commonly held view that condemnation is a 'passive' consequence, even wish, of the ungodly who are separated from God. [This is thought to preserve God's goodness in the eyes of those who can't swallow a just God who takes vengeance on those who reject him and persecute His people.] (2)V. 9b finishes with, "from the glory of his might". Certainly, it would be an odd thing to say that say that Paul is talking about being absent from His might as equivalent