Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.
Therefore the Lord himself shall give you a sign - since thou wilt not ask a sign, nay, rejectest the offer of one.
You - for the sake of the house of believing "David" (God remembering His everlasting covenant with David), not for unbelieving Ahaz sake. God had guaranteed the perpetuity of David's throne in the person of Messiah, David's seed (2 Samuel 7:16: cf. Ethan's psalm, Psalms 89:35-37; Psalms 132:11). Ahaz should have believed in God's promise, which made it impossible that the scheme of the two invading kings to set aside David's line of succession should succeed.
Behold - arresting attention to the extraordinary prophecy.
A virgin - from a root, to lie hid, virgins being closely kept from men's gaze in their parents' custody in the East The Hebrew х haa`almaah (H5959)] and the Septuagint here, and Greek х hee (G3588) parthenos (G3933)], Matthew 1:23, have the article, the virgin, some definite one known to the speaker and his hearers; primarily, the woman, then a virgin, about immediately to become the prophet's second wife, and to bear a child, whose attainment of the age of discrimination (about three years) should be preceded by the deliverance of Judah from its two invaders. The term ha'mah denotes a girl of marriageable age, but not married, and therefore a virgin by implication. Bethulah is the term more directly expressing virginity of a bride or betrothed wife (Joel 1:8). Its fullest significancy is realized in "the woman" (Genesis 3:15) whose 'seed should bruise the serpent's head,' and deliver captive man (Jeremiah 31:21-22, "O virgin of Israel, turn again ... for the Lord hath created a new thing in the earth, A woman shall compass a man;" Micah 5:3, "Therefore will he give them up, until the time that she which travaileth hath brought forth"). Language is selected such as, while partially applicable to the immediate event, receives its fullest and most appropriate and exhaustive accomplishment in Messianic events.
The New Testament application of such prophecies is not a strained 'accommodation;' rather the temporary fulfillment is an adaptation of the far-reaching prophecy to the present passing event, which foreshadows typically the great central end of prophecy, Jesus Christ (Revelation 19:10). Evidently the wording is such as to apply more fully to Jesus Christ than to the prophet's son. "Virgin" applies in its simplest sense, to the Virgin Mary, rather than to the prophetess, who ceased to be a virgin when she "conceived." "Immanuel," God with us (John 1:14; Revelation 21:3), cannot in a strict sense apply to Isaiah's son, but only to Him who is presently called expressly (Isaiah 9:6), 'the Child, the Son, Wonderful (cf. Isaiah 8:18), the mighty God.' The inspired authority of Matthew 1:23 decides the Messianic reference; for it cannot be a mere 'accommodation' of Scripture, since the Evangelist saith, "that it might be fulfilled which was spoken of, the Lord by the prophet, saying, Behold, a virgin," etc. Local and temporary features (as Isaiah 7:15-16) are added in every type: otherwise it would be no type, but the thing itself. There are resemblances to the great antitype sufficient to be recognized by those who seek them-dissimilarities enough to confound those who do not desire to discover them.
Shall conceive, and bear (Hebrew, is with child, and beareth) a son, and shall call his name Immanuel, -
i.e., she shall. So the Chaldaic, margin, and Septuagint, thou, O Virgin, shalt call. [But then the shªwa (ª) would be written under the Hebrew letter tau (t). The Hebrew verb is feminine in termination.] Mothers often named their children (Genesis 4:1; Genesis 4:25; Genesis 19:37; Genesis 29:32). In Matthew 1:23 the expression is strikingly changed into "they shall call." When the prophecy received its full accomplishment, no longer is the name Immanuel restricted to the prophetess' view of His character in its partial fulfillment in her son: all shall then call or regard Him as peculiarly and mostly fitly characterized by the descriptive name "Immanuel" (1 Timothy 3:16, "God was manifest in the flesh:" Colossians 2:9).
His name - not mere appellation, which neither Isaiah's son nor Jesus Christ bore literally; but what describes His manifested attributes; His character (so Isaiah 9:6). The name, in its proper destination, was not arbitrary, but characteristic of the individual. Sin destroyed the faculty of perceiving the internal being; hence, the severance now between the name and the character: in the case of Jesus Christ, and many in Scripture, the Holy Spirit has supplied this want (Olshausen).