Why was Jesus not called Emmanuel?

Answer 1

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."

Notice that this does not say that Jesus would be named Emmanuel, just that "the prophet" spoke of a son who would be called Emmanuel.

This is a reference to Isaiah 7:14, which the author of Matthew was seeking to use to show that the birth of Jesus was prophesied, and that his mother would be a virgin. In the days before the scriptures were marked by chapter and verse, it was necessary for him to somehow identify where the reference to the virgin birth could be found, and he knew that Isaiah 7:14 was the only reference to Emmanuel. In fact, the virgin birth could only be found in the Septuagint, a flawed early Greek translation of the Hebrew text. The original Hebrew only said "the young woman", not "a virgin", and the young woman in fact had a son a few verses later in Isaiah. English translation of the Christian Bible keep the Septuagint mistranslation, for consistency with the Book of Matthew.