Syria and the land of Ephraim. Both would be overrun by the Assyrians before the child would be old enough to discern between evil and good.
This prophecy was literally fulfilled in the days of Ahaz, but it had another fulfilment in the person of our Lord. According to Matthew (1:20-24), Joseph, when thinking of leaving Mary secretly, without causing a public scandal, had a dream, in which an angel appeared to him and explained that he had no cause against Mary. The evangelist adds that, all this was done, that it might be fulfilled which was spoken of the Lord by the Prophet, saying: "Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel." A most notable instance of the double application of a prophetic utterance!