"When I sharpen my shining sword." This means God is preparing to judge and punish his enemies. Alternate translation: "When I am ready to judge my enemies" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "hand" represents the whole person. Alternate translation: "when I get ready to judge the wicked" (See: [[rc://en/ta/man/translate/figs-synecdoche]])