Both of these phrases mean basically the same thing. Yahweh compares the king of Assyria to a weapon a person holds in his hand and hits other people with. It emphasizes that the king of Assyria and his army are a tool that Yahweh uses to punish Israel. Alternate translation: "who will be like a weapon in my hands that I will use to show my anger" (See: [[rc://en/ta/man/jit/figs-metaphor]])