tit-for-tat, 'an eye for an eye'

Psalm 137:1-9
How can we sing the song of the Lord while in a foreign land?
If I forget you, O Jerusalem, may my right hand forget its skill.
May my tongue cling to the roof of my mouth if I do not remember you, if I do not consider Jerusalem my highest joy.
How can the exiles sing to God in the foreign land of Babylon?
The old joyful melodies bring a lump to the throat.
Why?
Memories of the terrible destruction of their city and Temple overwhelm the. The pain of it comes out in a cry for vengeance: tit-for-tat, 'an eye for an eye'
The Israelites had no doubt witnessed just such atrocities 暴行 committed in Jerusalem by the Babylonian army.
How?
Remember the sat history is good if makes them repent and return to the Lord. So am I if I don't forget what the Lord have done to me.