Thomas Aquinas Commentary Lamentations 3:64-66

"Thou wilt render unto them a recompense, O Jehovah, according to the work of their hands. Thou wilt give them hardness of heart, thy curse unto them. Thou wilt pursue them in anger, and destroy them from under the heavens of Jehovah." — Lamentations 3:64-66 (ASV)

Here he asks for vengeance against his enemies. Because of his confidence that his prayer will be heard, he offers more of a prediction than a prayer. In this, he does two things.

1. He predicts the just retribution of sinners: you shall render them, that is, punishments. According to the works of their hands give to them: render to them their reward (Psalms 27:4).
2. He describes the determination of their punishment:
   1. First, concerning its duration: I will give them your labor, that is, the sin in which they made you suffer. I am weary of bearing them (Isaiah 1:14). a buckler of heart, that is, for their sins you will reward them by putting on their hearts a shield—a hardness—so that they are not penetrated by the arrows of your grace or by the sword of your word. His body is like molten shields (Job 41:6).
   2. Second, concerning the punishment of the body: you shall persecute them with various afflictions, and then, you shall destroy them by death and eternal damnation—under the heavens, those who wanted to be in the heavens. Bring upon them the day of affliction, and with a double destruction, destroy them (Jeremiah 17:18). So shall you pursue them with your tempest: and shall trouble them in your wrath (Psalms 82:16).