In the first chapter of the New Testament, we see the fulfillment of a prophecy that happened over 700 years ago.
Now there are some prophecies where we don't know if they are fulfilled, or (because of our system of Eschatology) we might have some disagreements about. But this one we know for sure - there is a passage in Isaiah 7, and this is the fulfillment.
Mt 1:22 Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying,
Mt 1:23 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.
Barnes, in his Notes on the Bible, writes,
However you read it, God spoke His word in the Old, and fulfilled it it in the New!