the house of David. Not to Ahaz only, but to the house which had received the promise of Jehovah's protection (2 Samuel 7).
Ephraim. The leading tribe, put by Figure of speech Synecdoche (of Part), for the rest of the ten tribes. Sometimes called "Samaria" (1 Kings 16:24).
His. i.e. Ahaz.
wind. Hebrew. ruach. App-9.