Some have argued that Hezekiah is the fulfillment of the various
prophecies in Isa 7, which is a view I used to hold to. However, such is a chronological impossibility. Ahaz
reigned sixteen years (2 Kgs 16:2; cf. 2 Chron 28:1) and was succeeded by his
son Hezekiah who began ruling at the age of twenty-five (2 Kgs 18:1-2; cf. 2
Chron 29:1). The date of the prophecy to "the days of Ahaz . . . king of
Judah" (Isa 7:1) presents a major chronological problem for this
hypothesis. Even though Pekah was in the last three years of his reign when
Ahaz too over the southern kingdom (2 Kgs 15:27; 16:1), Hezekiah would have
been somewhere between nine and twelve years of age, so it would have been too
late for Isaiah to have prophesied of his conception and birth or when he would
start talking (see Isa 7:13-25).