Augustine of Hippo

"Break the arm of the sinner and of the malicious"; of him, namely, of whom it was said above, "He shall have dominion over all his enemies." He called his power then, his arm; to which Christ's power is opposed, of which it is said, "Arise, O Lord God, let Your hand be exalted. His fault shall be required, and he shall not be found because of it;" that is he shall be judged for his sins, and himself shall perish because of his sin.

Exposition on Psalm 10 ↗

Thomas Aquinas

"Break." Here he announces his being heard. And first, as to sinners. Second, as to the poor, at "the desire of the poor," etc. Regarding the first, he does two things. First, he announces the cessation of the power of the wicked by which they inflicted evils. Second, the cessation of their evils themselves. As to the first, he says, "break the arm of the sinner," who sins against God. Is. 14: "The Lord has broken the arm, or the staff, of the wicked, the rod of those who struck the peoples," etc. …

Exposition on the Psalms of David ↗