The Greek ekdikēsis means the execution of justice — punishment of the guilty or vindication of the wronged. It is used of God's judicial vengeance (Romans 12:19; 2 Thessalonians 1:8), of the widow's plea for justice from the judge (Luke 18:7-8), and of the Thessalonians' suffering and God's just response. The word combines the ideas of punishing evil and defending the vulnerable.
The theology of ekdikēsis is not about revenge but about the restoration of right order by the only Judge who has perfect knowledge and perfect justice. Paul's command 'do not take revenge' (Romans 12:19) is grounded in God's own ekdikēsis — 'It is mine to avenge; I will repay, says the Lord.' Leaving vengeance to God is not passivity but an act of profound faith: trusting that the One who sees all will execute perfect justice. The widow's persistent prayer for ekdikēsis (Luke 18:3) is a model of persistent intercession.