35, 55, 58, 59, 69, 79, 83, 109, 137, 139)...Wishes or prayers for divine vengeance also occur with some frequency in other contexts...2 Samuel 3:28-29; 2 Kings 1:10, 12...; Nehemiah 4:4-5; Jeremiah 11:20; 15:15; 18:21-23; 20:12; Amos 7:17.” (P. 407)
The second person singular, present indicative active verb ἐκδικεÃς, ekdikeis means "you are avenging someone," "you are procuring justice for someone," "you are taking vengeance for something," "you are punishing something." It fits directly in line with the biblical motif of spilled blood, or injustice, or withheld wages, that "cry out" to YHWH, demanding justice. God cannot be the God of justice, unless He hears every such cry, and responds to such cries with His powerful judgment in history. It is one of the fundamental themes of the Jewish Bible that the Lord of history hears all such cries, and comes in
history (on His "day") to render judgment, delivering those whose cries have been heard, and punishing those who have caused the cries.
This prayer has been rejected as "sub-Christian," in the light of the prayer of Jesus on the cross, "Father, forgive them, for they don't know what they are doing" (found only in Luke 23:34, and there not in the earliest manuscripts, but only in later copies). But such a rejection makes far too much of this statement attributed to Jesus, neglecting the fact that Jesus foretold divine vengeance on Jerusalem and its religious leaders in no uncertain terms--see, for example, Mark 13, Matthew 23-24, and Luke 21.
We might conclude that while Jesus may have prayed for the forgiveness of sins done in ignorance, He at the same time proclaimed divine vengeance for willful opposition to the will of God! The biblical teaching concerning the God of justice and vengeance upon evil doers is a powerful corrective to many modern views of a non-historical, "namby-pamby" God who is little more than the projection of our wishes and sentimentalities!