The New Testament tells us that, according to the Old Testament prophecy, Jesus was born through a supernatural birth – his mother was a virgin. This is based on the verse Isaiah 7:14 where it says:

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

Rabbi Josef Mizrachi tried to challenge the New Testament’s claim, saying: “Never in history did anyone interpret the word ‘alma’ as virgin.” The truth is that many Jewish scholars, including Rashi, interpreted the word alma as virgin several times, as we will explain. But the Rabbis say that the concept of the “Virgin Birth” is pure paganism. Do they consider God unable to cause a virgin woman to conceive a child by means other than intercourse?
The word often translated as ‘virgin’ (betulah) in the Bible can actually refer to a married woman as well as to an unmarried woman, but the word ‘alma' refers to a young and specifically unmarried woman. According to the culture and to God’s commandments during biblical times, a young girl who never married would be presumed to be chaste. Therefore, the use of the word alma rather than betulah in this verse and prophecy, regarding the birth of the Messiah, actually confirms the fact that the Messiah was supposed to be born in a miraculous way.
But first, in order to have some background information, let’s understand what is happening in the context of this important chapter.

The context of the prophecy

Isaiah 7 begins with a description of King Ahaz, son of Jotham son of Uzziah, king of Judah. Unlike his father, Ahaz didn't walk in faith in the ways of the LORD, but was a wicked ruler and idol worshiper. He worshiped Baal and even offered his own sons as a sacrifice to his gods. His neighbors were not any better than him… In Aram, King Ratzin reigned, and in Samaria, Pekah son of Remaliah was the king of Israel. These two kings wanted to join the with Ahaz and his Kingdom of Judah to form a defense treaty against the king of Assyria, who at that time, had begun a campaign of conquest. But Ahaz refused to join them, so in response, the king of Aram and the king of Israel threatened to go to war against Judah. Their intention was to take down Ahaz and put a “puppet” king in his place. Since Ahaz didn’t trust in God, he knew that he had no chance of winning on his own, and turned to the king of Assyria, Tiglath-Pileser III, to beg for help. Along with the request, he also sent money and gold. Ahaz, a king from the house of David, was supposed to ask for help from the God of his fathers, but as in so many other cases like his, this story shows us that whoever puts his trust in people instead of God is destined for disappointment. The armies of Aram and Israel came up against Judah and besieged Jerusalem, but conquering the city was challenging due to the fortifications which were built there back in the days of Uziyahu, Ahaz’s grandfather. Because Ahaz failed to turn to God, God sent the prophet Isaiah to him, along with his son Shear-Jashub, to bring him words of encouragement.
The purpose of the prophecy was to remind Ahaz and his people that the lives of all people are in God's hands, and that everyone should believe and trust in Him. Isaiah came to Ahaz while he was observing the besieging enemies, and said: “These two smoldering stumps of firebrands.” The prophet describes Ratzin, king of Aram and Pekah son of Remaliah, king of Israel, as powerless. In God’s eyes, they are no more than a burning end of a tail, letting off smoke. Isaiah prophesies in verses 7-9 that the plan of the two kings plan to kill Ahaz and set up a “puppet” king in his place would fail. Ahaz, king of Judah, is seeing right in front of him the armies of Aram and Israel planning to destroy him. Yet in face of these facts, the prophet Isaiah promises Ahaz that they will fall. A prophecy that was fulfilled 65 years later.
The king must have thought: “How will this help me 65 years from now? I need a solution now!” In verses 10-11 God knew the king’s thoughts, and made a proposal in order to encourage him:

“Ask a sign of the LORD your God.” (Is. 7:10) In verse 12, King Ahaz, who did not regard for God, but worshiped idols, answered God sarcastically: “Ahaz said: ‘I will not ask, and I will not put the LORD to the test.'” (Is. 7:12)

God was willing to give king Ahaz a sign in order to cause him to trust and believe in him, but the insincere and hypocritical response of Ahaz proved the depth of his wickedness and contempt for God. He knew very well that if he asked for a sign that would come to pass, he would need to repent and change his ways. He wanted to keep the power and control in his hands. This response angered God. Now, the prophet Isaiah turns from Ahaz to the people, to the entire house of David, and says to them: “Therefore the Lord himself will give YOU [you all – pl.] a sign.” (Is. 7:14) Ahaz refused to ask for a sign, so God, by his own initiative, will give the people a sign.

When would it happen?

In the next verses we learn that this will be a difficult period for the people of Israel. The prophet indicates that “he will eat curds and honey.” Sounds good? Not in biblical times – curd is a by-product of milk, and as for honey, people needed to go into the woods, in a difficult search for beehives. That means that it would be during a time of hardship and deprivation. And indeed, Jesus was born in a time when the people of Israel sighed under the Roman occupation. “He knows how to refuse the evil and choose the good” Isaiah continues to describe the promised son from the alma, Immanuel: He would be good and perfect, he would refuse evil and will choose only what is good.Now we are also shown the reason why God asked Isaiah to bring his young son, Shear-jashub, with him. At this point, the prophet Isaiah turns back to king Ahaz, points to Shear-jashub, and says: “For before the boy knows how to refuse the evil and choose the good, the land whose two kings you dread will be deserted.” That means that before Isaiah’s son knew how to discern between good and evil, the two kings who were so feared by Ahaz and the people of Judah, would be removed from the earth. Sure enough, within two years, those two kings met their death.

The meaning of the word ‘Alma'

Now that we understand what is happening in chapter 7, we can go back to the meaning of the word ‘alma' in the Old Testament. In order to decide about the meaning of any word, we need to examine the context in which it appears, as we have done, and then compare it to all the other places where it appears.

The word ‘alma' appears in the Old Testament seven times, and the meaning is always a young, unmarried girl. In Genesis 24, Abraham's servant, Eliezer, comes to Nahor and prays that God will help him find the right wife for Isaac. There, Rebekah is described: “a young woman was very attractive in appearance, a maiden (alma) whom no man had known.” Later, Eliezer refers to her as “the alma“. In Exodus 2, we are told that Pharaoh's daughter pulled Moses out of the water. Moses' sister, Miriam, stood at a distance and watched the event. Then, she ran to Pharaoh’s daughter and offered to find a Hebrew woman to nurse the baby for her: “And Pharaoh's daughter said to her, “Go.” So the girl (alma) went and called the child's mother.” Miriam’s description in verse 4 testifies that she was a young girl, unmarried, as she still lived with her parents. In Psalm 68:25, “virgins (alma pl.) playing tambourines” are single women, who took part in the procession accompanying the king to the holy place. Proverbs 30:19-20 “the way of a man with a virgin (alma). This is the way of an adulteress: she eats and wipes her mouth and says, “I have done no wrong.” The author says that a man who intentionally leads the way with a virgin in sexual relations is like an adulteress who intentionally leads men astray but doesn’t admit her sin. In Song of Songs 1, Solomon’s bride praises him while she says that young women (alma pl.) who are looking for a husband, are attracted to him as a man who is about to marry her. In Song of Songs 6, three categories are mentioned of women who lived in the king’s palace: Queens, concubines and young women (alma pl.) The young women (alma pl.) were there to serve the queens and were kept under purity laws, which lasted an entire year. They had to be virgins, and to marry eventually. Therefore, the Old Testament always uses ‘alma'for an unmarried woman, who is also a virgin.
Another question we need to consider is how the word ‘alma' was understood in ancient Judaism. The Septuagint is a Greek translation of the Old Testament made by 70 Jewish scholars long before the time of Jesus, and they translated the word ‘alma' in Isaiah 7:14 to mean ‘virgin'. The Pshitta, a Syriac translation from Hebrew undertaken in the 2nd century CE, also translated ‘alma' as ‘virgin'. And so did the Vulgate translation into Latin.
The Jewish biblical scholar Dr. Fruchtenbaum writes that the rabbis quote Rashi as someone who interprets the word ‘alma' as a ‘young woman,' and concedes that Rashi does indeed consider the word in Isaiah 7:14 to refer to a young woman rather than a virgin. However, Fruchtenbaum points out that it's easy to understand why Rashi would take a different position in this particular case: he was involved in polemical debates against Christians, and therefore he took an opposite position to the one which had been accepted up until his time in order to try and disprove Yeshua's messiahship. In fact, he took a different position to the one that he himself held in a different case – Rashi didn’t always interpret the word ‘alma' as a ‘young woman'. This word also appears in the Song of Songs, and in these verses, he interpreted ‘alma' as a ‘virgin'. Moreover, Rashi himself indicated that other Jewish scholars producing Biblical commentary in his time also interpreted the word ‘alma' in Isaiah 7:14 as a ‘virgin'.
And it is important to note that the ancient Jewish Sages also held the belief that the Messiah wouldn’t have a biological father. Here is what they taught –
“The redeemer whom I shall raise up from among you, will have no father”
(Genesis Rabbah of Rabbi Moshe haDarshan)