So Isaiah gave Ahaz a sign anyway.

“Behold, the virgin will conceive, and bear a son, and shall call his name Immanuel.” Isa 7:14 WEB

The World English Bible (WEB) is correct here: “the virgin shall conceive.” The Hebrew word for a virgin is almah, and it describes an unmarried “maiden,” who would in normal circumstances would be a virgin. The word also occurs in Gen 24:43, Ex 2:8, Psa 68:25, Prov 30:19, and Song of Solomon 1:3, 6:8. Jewish translators around 200 BC when translating the Old Testament into Greek, choose to translate the word as the Greek parthenos, which is unequivocally a virgin.

And what will happen with this child born of
a virgin?

It seems to speaking in the immediate context of Ahaz and Judah’s dilemma. It seems to speak of child to born soon. This child will eat curds and honey (KJV) and before the child is old enough to refuse the evil and choose the good (just a small number of years) the land of the two kings who are fighting against Ahaz, will be abandoned,
Isa 1:16!

In other words, Isaiah confirms what he told Ahaz earlier, that Israel and Aram will not be able to overcome Judah … without the interference of any foreign powers.

It is widely debated who the “almah” is.

Some say it was a wife of Ahaz. In Prophecy Principles, in the section called “We Sit,” I discussed the prophecy as if it had reference to Isaiah’s wife having a baby, and how that would be analyzed. Other also have done the same or similar things. Clearly Isaiah is telling Ahaz that he should NOT enter treaties with pagan powers, but that he should trust in the Lord, and everything will be alright. This would be the first prophecy.

But as we have already seen, trusting God or believing God, is not in Ahaz vocabulary.

But STILL there is the implicit contradiction of a
virgin (rather “the virgin”) having a baby.

Isaiah has one of his sons with him when he meets Ahaz, Isa 7:3. She is sometimes represented as one of Ahaz’s wives or whoever. But still … how can you call them a “virgin.” That is the implicit tension in the prophecy. These are signs of a type, when something does not really fit.

And of course there is still to be considered
Isaiah’s master subject: the Messiah.

He was to come as a child, and to be “Mighty God, Eternal Father” in Isa 9:6 WEB as discussed in Part III of this series.

So how does “THE virgin” conceive a child?

The answer of the angel is,

“The Holy Spirit will come on you, and the power of the Most High will overshadow you. Therefore also the holy one who is born from you will be called the Son of God.”
Lk 1:35 WEB

Of course this would be no big trick with the God who made heaven and earth and everything they contain. This would be second prophecy, and the true anti-type of whoever had a baby in the eighth century BC.

Your answer may depend on whether you decide to a priori rule out God as working in history!

KJV is the King James Version, 1611.

WEB is the World English Bible, a copyright free revision
of the original ASV American Standard Version 1901