Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel. Butter and honey shall he eat, that he may know to refuse the evil, and choose the good.

Isaiah 7:14-15

Explanation:
In verses 10 to 13 God offers to give Ahaz a sign so that he would trust God. Ahaz feigned a pious answer and refused a sign from God. When we read verse 14 we realize that God would not be refused. He gives Ahaz a sign anyway.

Verse 14 may be one of the most well-known verses in Isaiah. We often hear this verse around Christmas time because of its clear reference and fulfillment in the conception and birth of Jesus Christ. Matthew quotes this verse regarding the conception and birth of Christ in Matthew 1:22-23.

Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying, Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us.

Matthew 1:22-23

So we know, by the inspiration of the Holy Spirit, that Isaiah 7:14 definitely refers to Christ.  Jesus Christ was definitely born of a virgin, Mary.  In Luke 1 an angel came to Mary and told her that she had conceived and would have a son.  Look at Mary’s response:

Then said Mary unto the angel, How shall this be, seeing I know not a man? And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God.

Luke 1:34-35

The virgin that would conceive which was foretold in Isaiah 7:14 definitely referred to Mary. Christ was supernaturally conceived by the Holy Spirit, and could rightly be called the Son of God.
When we read Isaiah 7:14-15 in its context there is clearly a sign that is being given to Ahaz. Ahaz had refused God in asking for a sign (Isaiah 7:12), and had wearied God and man in not trusting in God (Isaiah 7:13). The sign being given is also then a sign to Ahaz.
When reading this verse in the context of Isaiah 7 several positions have been taken.

1. Isaiah 7:14 is only fulfilled in the day of Isaiah. This is problematic because Matthew teaches that it speaks to Mary and to Christ.
2. Isaiah 7:14 is only fulfilled in the day of Christ. This is problematic because there is a specific reference to timing in verses 15 and following. The sign of this son named Immanuel would signify that before this son was old enough to discern good and evil (a reference to his age) “the land would be forsaken of both of her kings” (Isaiah 7:16).
3. Isaiah 7:14 has both an immediate fulfillment in Isaiah’s day, and ultimately is fulfilled in Christ. This seems to be the correct interpretation, but one must be able to answer several questions in this view as well. Is the son born in Isaiah’s day “born of a virgin”? Bible commentators like Warren Weirsbe and others contend that the woman spoken of in Isaiah’s day was then (at the time of the prophecy) a virgin but would conceive and bring forth a son. Others concede that the Hebrew word for virgin could also mean “young woman” or “maiden”. Many arguments have been made through the years about this word. Unfortunately, people have taken this argument to try to make the point that Jesus was not born of a virgin, but of a “young woman” and therefore his birth was not supernatural, and he is not God. He would then be born with a sin nature, and we are still in our sins. Matthew, Luke and many other New Testament writers leave no room for the idea that the conception of Christ is anything less than miraculous. Mary became pregnant supernaturally, and Christ is the Messiah, the perfect, sinless Son of God. What is amazing and proof of this third position is that every part of this prophecy was fulfilled! The land was forsaken of both her kings before the timeframe of this son being old enough to discern right from wrong, and a virgin did conceive, and brought forth a son who was literally “God with us”, Jesus Christ.

Application:
Don’t miss the point of the big idea of this text. God can be trusted. What He says will come to pass. Jesus Christ is God in the flesh. When we understand why He came and trust in Him to pay for our sins, we are saved. When we doubt who He is, and reject Him as Savior, the consequences are stark. We will spend an eternity separated from God, paying for our sins. When God makes a promise, not only can He be trusted, but He must be trusted. The consequences of doubting God are grave!

Response:
Are you doubting God, or trusting Him today?