Therefore the Lord himself will give you a sign. Behold, the virgin will conceive, and bear a son, and shall call his name Immanuel.

Isaiah 7:14

In the 7th century B.C., Pekah the king of the northern kingdom of Israel, had formed an alliance with Rezin the king of Syria, to resist the Assyrian empire, led by king Tiglath-pileser (2Ki 15:29). When king Ahaz of Judah refused to join their alliance, Pekah and Rezin invaded Judah (2Ki 15:37), and laid siege to Jerusalem (2Ki 16:5, Isa 7:1). To resist them, Ahaz formed an alliance with Tiglath-pileser (2Ki 16:7-9), but the prophet Isaiah counseled him to trust only in Yahweh for deliverance (Isa 7:2-9). Yahweh offered to give Ahaz a miraculous sign, as a token of his favor, and assurance of his ability and willingness to save Jerusalem (Isa 7:10-11).

But Ahaz refused to ask for a sign (Isa 7:12), so in exasperation (Isa 7:13) God revealed that he would give a sign to Ahaz anyway (Isa 7:14-16): a young, unmarried woman would have a baby, and before the child “knows to refuse the evil, and choose the good” (ie. about three to five years), Pekah and Rezin would be gone (Isa 7:16). The child would be named “Immanuel”, meaning ‘God with us’, to signify God’s continuing care for his people (Deu 5:2, 1Ki 8:57, 2Ch 32:8, Psa 46:7, Isa 8:10).

This prophecy seems to be a parallel with that of Isaiah 8:3-4:

Isa 8:[3] I went to the prophetess, and she conceived, and bore a son. Then Yahweh said to me, “Call his name ‘Maher Shalal Hash Baz.’ [4] For before the child knows how to say, ‘My father,’ and, ‘My mother,’ the riches of Damascus and the plunder of Samaria will be carried away by the king of Assyria.”

Here, the name of the child is not ‘Immanuel’, but ‘Maher Shalal Hash Baz’ (meaning ‘Hurry to the prey, hasten to the plunder’). However, the name ‘Immanuel’ does occur in verses 8 and 10:

Isa 8:[8] It will sweep onward into Judah. It will overflow and pass through; it will reach even to the neck; and the stretching out of its wings will fill the breadth of your land, Immanuel. … [10] Take counsel together, and it will be brought to nothing; speak the word, and it will not stand: for God is with us.”

God was giving king Ahaz a sign of his continued care and presence with Israel, even when it appeared as if God had abandoned his people. The sign would not be immediately obvious; the physical manifestation of it wouldn’t even appear for months to come. But for those who trusted in God’s ability to fulfill his promises, and his goodness to keep his promises (Heb 11:6), it was a comforting sign that God would save his people from all their enemies.

The Hebrew word translated ‘virgin’ (almah; עלמה – H5959) in Isaiah 7:14 does not mean precisely the same thing as the English word ‘virgin’. It technically refers to a “young woman”, without reference to any sexual experience (Gen 24:43, Exo 2:8, SoS 6:8). Jewish interpreters sometimes argue that almah doesn’t necessarily refer to a woman who is a virgin, citing Proverbs 30:19. However, almah also implies that the woman is unmarried, though old enough to marry. This is in contrast to another Hebrew word, bethulah (בּתוּלה – H1330), that can also mean ‘a virgin’, but can also refer to a young woman who is betrothed, or even married (Joel 1:8). Only the word almah refers to a woman who is both a virgin, and unmarried.

In the Septuagint, almah is translated by the Greek word, parthenos (παρθένος – G3933) which does mean ‘virgin’, as we understand it in English. The Septuagint translation of Isaiah 7:14 is cited by the Apostle Matthew as a proof of the miraculous birth of Jesus Christ:

Mat 1:[22] Now all this has happened, that it might be fulfilled which was spoken by the Lord through the prophet, saying, [23] “Behold, the virgin {parthenos} shall be with child, and shall give birth to a son. They shall call his name Immanuel”; which is, being interpreted, “God with us.”

This shows that the prophecy in Isaiah 7:14 was not only intended as a message of comfort for the house of David at the time, but as a message of comfort for all the people of God ever since. It had its physical fulfillment in the days of Ahaz, but had its greater, spiritual fulfillment in the miraculous birth of Jesus Christ.

The fact that Jesus was born shows that he is truly a human being. The fact that he was born of a virgin shows that he was completely without sin:

There is only one man among the descendants of Adam born without a sinful nature, and this is Jesus of Nazareth, God the Son incarnate. He was born of a virgin by the power of the Holy Spirit, contracting no guilt or defilement from Adam. He was totally and completely without sin. [Isa 7:14; Isa 53:9; Mat 1:25; Luk 1:31-35; 2Co 5:21; Heb 4:15; Heb 7:26-27; 1Pe 2:22-23; 1Jo 3:5] Christian Confession of Faith, IV.A.1

The humanity and sinlessness of Jesus are foundational to the Gospel, because only a human could serve as a sacrifice to God for the sins of humans, and only a pure and sinless sacrifice could be pleasing and acceptable to God. And finally, only a person who combined a human nature with a divine nature could reconcile man to God.

Jesus of Nazareth is really and truly God as well as really and truly human. He is the only descendant of Adam with two natures, human and divine. These two natures are continually without confusion, without change, without division, and without separation. Scripture rejects the lie that Jesus Christ was merely human and not fully divine. It likewise rejects the lie that Jesus Christ was a supernatural being but not fully human. [Deu 18:15; Psa 2:7; Psa 110:1; Isa 9:6; Luk 2:7; Joh 1:1,14,18; Joh 3:16,18; Joh 5:18; Joh 8:58; Joh 10:30-33; Act 20:28; Rom 1:3; 1Co 15:47; Gal 4:4; Phi 2:6-8; Col 1:15; 1Ti 3:16; Tit 2:13; Heb 1:1-5; Heb 5:5; 1Jo 4:9,15; Rev 1:17-18] Christian Confession of Faith, IV.A.2

That Jesus did have a divine nature is shown throughout Scripture. First, Jesus himself claimed to be God:

Joh 5:[18] For this cause therefore the Jews sought all the more to kill him, because he not only broke the Sabbath, but also called God his own Father, making himself equal with God.

Joh 8:[58] Jesus said to them, “Most certainly, I tell you, before Abraham came into existence, I AM.”

Joh 10:[30] I and the Father are one.” [31] Therefore Jews took up stones again to stone him. [32] Jesus answered them, “I have shown you many good works from my Father. For which of those works do you stone me?” [33] The Jews answered him, “We don’t stone you for a good work, but for blasphemy: because you, being a man, make yourself God.”

Second, Jesus often received worship (Mat 14:33, Luk 24:52, Joh 9:38, Joh 20:28, Rev 5:12-14), without rebuking the worshipers, as the Apostles and the angel of Revelation did to those who tried to worship them (Act 10:25-26, Act 14:11-15, Rev 19:10).

Third, Jesus forgave sins:

Mar 2: [5] Jesus, seeing their faith, said to the paralytic, “Son, your sins are forgiven you.” [6] But there were some of the scribes sitting there, and reasoning in their hearts, [7] “Why does this man speak blasphemies like that? Who can forgive sins but God alone?”

Luk 5:[20] Seeing their faith, he said to him, “Man, your sins are forgiven you.” [21] The scribes and the Pharisees began to reason, saying, “Who is this that speaks blasphemies? Who can forgive sins, but God alone?”

Fourth, we are told that Jesus existed before the world began:

Mic 5:[2] But you, Bethlehem Ephrathah, being small among the clans of Judah, out of you one will come out to me that is to be ruler in Israel; whose goings out are from of old, from ancient times.

Joh 1:[1] In the beginning was the Word, and the Word was with God, and the Word was God. [2] The same was in the beginning with God.

Joh 17:[5] Now, Father, glorify me with your own self with the glory which I had with you before the world existed.

Col 1:[17] He is before all things, and in him all things are held together.

Heb 7:[3] without father, without mother, without genealogy, having neither beginning of days nor end of life, but made like the Son of God), remains a priest continually.

We are also told that he descended from Heaven, and returned there:

Joh 3:[13] No one has ascended into heaven, but he who descended out of heaven, the Son of Man, who is in heaven.

1Co 15:[47] The first man is of the earth, made of dust. The second man is the Lord from heaven.

And finally, in Revelation 2:8, we are told that God (who is “the first and the last”) died and then came to life. Only Jesus Christ could make this claim.

All of these facts show us that Jesus Christ partakes of the nature of God. He is, at the same time, Man and God. Indeed, the Gospel would not be possible unless he shared in both the nature of human beings and the nature of God. Without this dual nature, he could not appease the wrath of God against the sins of his people, and he could not mediate between God and man. This is the full importance of his nature as the God-man mediator. He is Immanuel, God with us.

11 Our God, who is the Lord of hosts,
is still upon our side;
The God of Jacob our refuge
for ever will abide.
(Psalm 46, The Psalms of David in Metre)

See Also:

A Christian View of the Messiah

An Open Letter to a Jehovah’s Witness

IV. Christology – The Doctrine of the Person and Work of Jesus Christ