Isaiah 7

11 God knew Ahaz hesitated to believe, so He invited him to choose a miraculous sign. Such signs helped such men as Abraham and Moses to believe. God allowed the timid Gideon to choose his own signs (Judg 6:36-40).
12 Ahaz appears to doubt not only doubted God's prophecies, but His existence as well. In a false show of piety he alludes to Deu 6:16 and refuses to name a sign.
13 While Ahaz thought that this could be the only answer that would not get him into trouble, God saw right through his unbelief. By not choosing a sign when asked to, Ahaz inadvertently tests God -- the very thing he claimed he was trying to avoid. Isaiah then warns Ahaz that he has tested the patience of both man and God.
14 If Ahaz would not choose a sign, then God would give one for him. The sign involved a woman (who was currently a virgin) giving birth to a son.

Some believe that this refers to Isaiah's own family and point to Isa 8:1-4. However, Isa 7:3 states that Isaiah already had a son. So if this refers to Isaiah's family, then he would have married the prophetess between this time and 8:1. The other thing to note is that the son in Isa 8:3 is not named "Immanuel." So if this verse does refer to Isaiah's family, it concerns a son that was not otherwise recorded. It seems likely that this refers to an unnamed woman somewhere in Judah.

In the context of the time, this verse does not appear to necessarily have a Messianic interpretation. It is not until Jesus is born that the Messianic significance of the verse is revealed (Mat 1:18-23, Luke 1:26-35). Thus, this verse is a double prophecy with both immediate and long-term meanings.

15 Wycliffe suggests that curds and honey would be eaten after Judah was invaded. Presumably, produce and meat would be confiscated and destroyed by the invading forces. People would rely on the milking animals that remained and wild honey.
16 Various authors have suggested anywhere from three to twelve years old as being the age of accountability. I prefer twenty years because this was the age of accountability for the Israelites during the time of the Exodus (Num 14:29).
17 The king of Assyria would be more destructive to Judah than the civil strife that broke the original kingdom of Israel apart.