Isaiah 7:2

2. Told the house of David This signal phrase refers not to the court of Ahaz, but to the blood royal, the lineage; as in modern phrase, “the house of Bourbon,” “the house of Brunswick.” So always, as 1 Kings 12:19: “Israel rebelled against the house of David unto this day;” as also 1 Kings 12:16 and 1 Kings 12:26, same chapter. And in Nathan’s memorable message to David, (2 Samuel 7:0,) the king was told that as he had purposed to build Jehovah a “house,” so Jehovah would build him “a house,” that is, a royal lineage. “Thine house and thy kingdom shall be established for ever before thee.” 2 Samuel 7:16. And David replies, (2 Samuel 7:18; 2 Samuel 7:25, and 2 Samuel 7:29,) “Bless the house of thy servant that it may continue before thee for ever.” And so Luke 1:27: “To a virgin… of the house of David.” Illustrious was the pedigree of that house, as given by Luke, beginning with Adam and the fall, and reaching to the Messiah. And never yet, in Ahaz’s time, had the line of David on the throne been broken. The royal line in the northern kingdom had been changed by a succession of usurpers, of whom this Pekah was then the last one. Doubtless the royal family of David realized their high descent, and were most deeply alarmed at the thought that its sacred continuity should be broken, and a usurper, the son of Tabeal, should break the promised line.

His heart David’s “heart,” ideally identified with David’s “house;” and so his people, no other than David’s.