Elisha uses this rhetorical question to emphasize that he and the king have nothing in common. This question can be translated as a statement. AT: "I have nothing to do with you." or "I have nothing in common with you." (See: [[rc://en/ta/man/translate/figs-rquestion]])
Here the "hand of Moab" refers the Moab's "control." AT: "to give them over to the control of Moab" or "to allow them to be captured by the Moabite army" (See: [[rc://en/ta/man/translate/figs-metonymy]])