This continues the message from Yahweh, given by Isaiah, the prophet, for King Hezekiah concerning King Sennecherib. It uses parallelism throughout. (See: [[rc://en/ta/man/jit/figs-parallelism]])
To make the point strongly this question assumes the listener knows the answer. Alternate translation: "Surely you know how ... times." (See: [[rc://en/ta/man/jit/figs-rquestion]])