Since it is a righteous thing with God to repay affliction to those who afflict you,
to recompense tribulation: The word "recompense" (antapodidomi) means "to repay, requite" (Thayer 49-1-467). Thayer comments that in this passage it is used in a bad sense of penalty and vengeance (Romans 12:19; Hebrews 10:30). The word "tribulation" (thlipsis) means "a pressing, pressing together, pressure,...oppression, affliction, tribulation, distress, straits" (Thayer 291-1-2347).