Psalms 94:1
KJV 1 O Lord God, to whom vengeance belongeth; O God, to whom vengeance belongeth, shew thyself.
Thomson 1 A Psalm by David for the fourth day of the week. The Lord is a God of vengeance, the God of vengeance hath given solemn warning.
These are my thoughts.
Vengeance is for the Lord to take and we need to let Him have it from us because for us to take it would be sin.
There is an event in Numbers 25 -- This event is called Ba'al of Pe'or. 25:3-9 / 3- So Israel was joined to Ba;al of Pe;or, and the anger of the Lord was aroused against Israel.
4- Then the Lord said to Moses, Take all the leaders of the people and Hang the Offender's before the Lord, out in the Sun, that the fierce anger of the Lord may turn away from Israel.
5- So Moses said to the Judges of Israel, Every one of you Kill his men who were Joined to Ba'al of Pe'or.
6- And indeed, One of the children of Israel came and presented to his brethren a Midianite woman in the sight of all the Congregation of the children of Israel, who were weeping at the door of the Tabernacle of meeting.
7- Now when Phin'e-has the son of Eleazar, the son of Aaron the Priest, saw it, he arose from among the congregation and took a Javelin in his hand;
8- And went after the man of Israel into the Tent and Thrust both of them through, the man of Israel, and the woman through her body, So the Plague was stopped among the children of Israel.
9- And those that died in the Plague were Twenty-four thousand!!
Did Phinehas Sin by killing these two people, God in verse 12 give's Phinehas the Covenant of Peace for his Action's!!
No! Moses was not taking actin, to verse [5] God made judgement! Phinehas just completed the execution.
Throughout the OT Men did to their Enemies as God gave them favor, God's Judgement was worked through the Men He Chose!