The Lord said unto me, Go up against this land, and destroy it; literally, Jehovah said unto me, Go up, etc.. The heathen monarchs frequently represented themselves as directed to make war on a nation by God, or by some particular god.
Piankhi Mer-amman says, "I am born of the loins. created from the egg, of the Deity … I have not acted without his knowing; he ordained that I should act". Mesha, King of Moab, declares, "Chemosh said to me, Go and take Nebo [in war] against Israel".
Asshur is generally represented as commanding the expeditions of the Assyrian kings. Still, it is surprising that Sennacherib should mention "Jehovah" as the God from whom he had received the order to attack Hezekiah, and we may suspect that the term which he actually employed was Ilu, "God," and that either Rahshakeh, or the reporter of the speech, substituted "Jehovah" as more intelligible to the Jews.