Psalms 17:13 - Matthew Poole's English Annotations on the Holy Bible

Disappoint him, Heb. prevent his face, i.e. go forth against him, and meet and face him in battle, as enemies use to do. Or, prevent the execution of his mischievous designs against me; stop him in his attempt, and give him the first blow. Which is thy sword; or, thy hand, as it follows, Psalms 17:14, i.e. thy instrument to execute vengeance upon thine enemies, or to chastise and exercise thy people; for which reason the Assyrian is called God's rod, Isaiah 10:5, as being ordained for correction, Habakkuk 1:12. The sense is, Do not punish me by this rod; let me fall into thy hands, and not into the hands of wicked men, 2 Samuel 24:14. Or, by (which preposition is understood Psalms 2:12, and oft elsewhere) thy sword, i.e. by thy power.