1. The sign given must be something “as deep as Sheol or as high as heaven” (7:11; Minnick, Sermon on 18 Dec 11; Mackay, EPSC, 204; Rydelnik, 818). It is a notable thing to which Isaiah can say, “Behold!” A young woman having a son is not a sign of this nature.
2. The term עַלְמָה refers to “a young unmarried woman who is a virgin.” This sense “fits all seven uses and can be denied in none of them” (Compton, 8; cf. Motyer, Isaiah, 84–85; Hess, Song, BCOT, 51; Rydelnik, 820-21). The LXX confirms this understanding of the Hebrew by translating with a word that unambigously means virigin. Thus the sign in Isaiah 7:14 is that a virigin will be pregnnat. (On the term בְתוּלָה referring to a maiden but not necessarily a virgin, see Wenham, “A Girl of Marriageable Age” VT 22.3 (Jul 1972); Bush, Ruth, WBC, 361; Adele Berlin, Lamentations, OTL, 122).
3. There is a parallel between the sign in Isaiah 7:14–16 and the oracle that accompanies Maher-shalal-hash-baz in 8:3–4. Before each boy reaches a certain age, Syria and Israel will be eliminated as a threat. However, Maher-shalal-hash-baz cannot be the Son of Isaiah 7:14
3.1. Isaiah’s wife (the prophetess) is not a virgin; Isaiah already has a son, Shear-jashub (Compton, 9).
3.2. Isaiah 8:4 seems to refer to events that took place in 732 BC, when Assyria defeated Israel and Assyria and took captives (1 Kings 15:29; 16:9). However, the kingdom of Israel continued for some time, so Isaiah 7:16 may refer to the fall of the kingdom in 722 BC (1 Kings 17:6). Note: The statement in Isa. 7:8 that within 65 years “Ephraim will be shattered, so that it is no longer a people” (NASB) seems to have been fulfilled in 671 BC (1 Kings 17:2).
3.3. Immanuel also appears in Isaiah 8:8. The land is identified as “your land, O Immanuel,” which links Immanuel to the Davidic royal line and thus distinguishes him from Maher-shalal-hash-baz, the son of Isaiah.
4. The name Immanuel, God with us, points to this Son truly being God with us. This is especially the case within the context of Isaiah 2–12. In chapter 2 Yhwh was said to reign from Zion, in chapter 4 the branch (a Davidic title; 11:1) is implied to rule in Zion, in chapter 7 the birth of a child who is named God with us is prophesied, in 8:8 Immanuel is said to be the possessor of the land (implying a kingly role), in 9:7 a Davidic king who is called “Mighty God” is promised, and in Isiaah 11 the Spirit-empowered Davidic king rules over all the nations with justice. Thus, within this section of Isaiah, the reader should be primed to see the birth of a child, in connection with the Davidic covenant, who is also identified as God.
Conclusion: Isaiah 7:14 is a direct messianic prophecy.
• The most significant challenge to the direct messianic prophecy view is the claim that Immanuel must be a certain age before the lands of Israel and Syria are deserted. There are two options here:
1. Even though Immanual is born many years after these events, the time frame of “before the boy knows how to refuse the evil and choose the good” is abstracted from his actual life an applied to the period between this prophecy and the conquest of Israel and Damascus in 732 BC (1 Kings 15:29; 16:9) or fall of Israel in 722 BC (1 Kings 17:6).
1.1. In support of this view, it is important to note that there are two threats that Isaiah is addressing. The threat to the Davidic house, addressed with plural pronouns to the whole house of David (7:14–15). The threat to Ahaz’s kingdom, addressed singularly to Ahaz (7:16–17) (Compton, 11–12; cf. Rydelink, 818).
1.2. The birth of Immanuel addresses the first threat; the time frame addresses the second threat. This provides a rational for abstracting the time frame from the actual life of Immanuel.
2. Because Ahaz lacked faith, the fulfillment of the sign will take place many years after the events. It will be long “before the boy knows how to refuse the evil and choose the good” that the lands of Israel and Syria will be deserted.
2.1 There are two types of signs in Scripture: (1) Present persuader (Ex. 4:8), (2) Future confirmation (Ex. 3:12).
2.2. Ahaz was offered a sign that would be a present persuader in verse 11, but due to his unbelief the sign given is a future confirmation (Jaeggli, Lecture, 20 January 2006).
At present I’m inclined toward option 1.