Psalm 35 reveals that we can pray what might, on the surface, appear to be pretty ruthless prayers.
Let them be put to shame and dishonor
who seek after my life!
Let them be turned back and disappointed
who devise evil against me!
Let them be like chaff before the wind,
with the angel of the Lord driving them away!
Let their way be dark and slippery,
with the angel of the Lord pursuing them!
(Verse 8)But contrast the prayers for vindication in this psalm to the way the world thinks about vengeance:
Let destruction come upon him when he does not know it!
And let the net that he hid ensnare him;
let him fall into it—to his destruction!
The worldly person, the one who is without God, has to take matters into his own hands. He has no God upon whom he can call, no God who will take up his cause.
The Christian, however, can petition the Almighty God, the LORD of the universe, to take vengeance on his behalf, with the implicit understanding that he, the Christian, will not take matters into his own hands. He will trust in the LORD. The Christian can call upon the LORD, whose attributes of protection and deliverance are contained in his name "Yahweh," and can rest in knowing that the LORD, in His infinite wisdom, will make all things right in His own time. From the Got Questions? website:
"Yahweh is present, accessible, near to those who call on Him for deliverance (Psalm 107:13), forgiveness (Psalm 25:11) and guidance (Psalm 31:3)." (What are the names of God, and what do they mean? - Got Questions?)Also see: Psalm 135:14 "For the LORD (Yahweh) will vindicate his people and have compassion on his servants."
Sons of Korah, A Recommended Resource
The Psalms (sermon by Dr. R.C. Sproul)
Wisdom for Spiritual People – The Message of The Psalms (sermon by Dr. Mark Dever)