Charles Ellicott Commentary Matthew 1:22

"Now all this is come to pass, that it might be fulfilled which was spoken by the Lord through the prophet, saying," — Matthew 1:22 (ASV)

All this was done — The Evangelist pauses in his narrative to introduce his own comment. He saw in what he relates that which answered to the apparent meaning of prophetic words. He could not possibly regard the agreement as a chance coincidence; and, as chance was excluded, there was no alternative but purpose. The prophecy and the event both entered into a divine plan.