These verses continue the description of the final war for the city of Jerusalem and of how God will save it. In this prophecy, Yahweh is described as a warrior who will come and fight in battle.
This can be stated in active form. AT: "The presences of Yahweh will split the Mount of Olives ... causing there to be a very great valley" (See: [[rc://en/ta/man/translate/figs-activepassive]])