Yahweh uses this question to emphasize that he was the one who brought Gog to the land of Israel. AT: "You are the one ... bring you against them." (See: [[rc://en/ta/man/translate/figs-rquestion]])
Here "hand" refers to the fact that these prophets wrote down Yahweh's message. AT: "by means of my servants" or "through my servants" (See: [[rc://en/ta/man/translate/figs-metonymy]])