This metaphor is a command for Jeremiah to get ready to do what God commands him to do as if he were tucking his clothes into his belt so he could do physical work or fight in battle. Alternate translation: "Get ready for action" (See: [[rc://en/ta/man/jit/figs-metaphor]])
Here "be shattered" represents being extremely afraid, and "shatter" represents causing Jeremiah to be extremely afraid. Alternate translation: "Do not be terrified ... I will terrify you" (See: [[rc://en/ta/man/jit/figs-metaphor]])