What does 2 Thessalonians 1:9 mean?

The result of unbelief is eternal punishment. The wicked will not be annihilated or experience only a temporary punishment. Their punishment will be everlasting suffering in hell. Jesus warned against being "thrown into the eternal fire" (Matthew 18:8). Matthew 25:41 reports that at the Judgment of the Nations Jesus will tell unbelievers, "Depart from me, you cursed, into eternal fire prepared for the devil and his angels." Referring to those unbelievers, Matthew 25:46 says, "And these will go away into eternal punishment."

According to 2 Thessalonians 1:9, the punishment of unbelievers in hell will consist not only of suffering in the "fires," but also banishment from the presence of the Lord. The word translated "presence" is literally "face." Whereas believers will see the Lord face to face (1 Corinthians 13:12), unbelievers will be driven from the face of the Lord and will never know the joy of being in His presence and the delight of observing the splendor of His power. Their knowledge and shame at this destiny is part of their suffering in eternity.