Matthew 1:20-23
20.But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost.
21. And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins.
22. Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying,
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.
One issue of this thread seems to be centered around vs. 21 in the identification of who "his people" refers.
I do hope all would agree that here the "his" refers to Jesus, the Son.
Some would make the identification based on the Biblical account of what did happen and who was saved.
But that ignores what might happen in the future for sometimes prophetic statements can have a division of many, many years even in the middle of the sentence as exampled by the following:
Isaiah 9:6 (King James Version)
6For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace.
A child is born (present tense), and a son is given (present tense); but is the government upon his shoulder?
"the government shall be" (future tense).
Whether one feels that future was only future to the writer, or yet future to us is certainly debatable; but in either case, there is a separation of the time frame in the middle of sentence.
IMO to properly identify the "his people" in vs.21 one must seek to identify the time frame and determine if a time frame in which Jesus could or did "save his people" is over and past, active today, or yet in the future.
The passage in question by the OP, Mt 1:20-23, is the fulfillment of Isa 7:14. Some might question who is the audience of passage from Matt, but do they also question to whom the Isaiah passage is written?
Back to the time frame issue.......
Is the government on His shoulders?
Some say no, that will come in the future Millennial Kingdom and then the prophetic statement of Matt 1:21 will come true and Jesus will save His people by keeping the promises made by God in the OT to the nation of Israel.
Those holding the above premillennial view will also interpret the "his people" to be the nation of Israel.
However, some say yes, the government is on His shoulders today, not physically, but spiritually for Christ is ruling and reigning in the hearts of the Christian even now.
Therefore those holding the above amillennial view will also interpret the "his people" in a much broader sense as covering many more folks than just the nation of Israel.
So now I ask those holding the amillennial view if the Matt passage in question physically happened, was Jesus physically born of a virgin, physically conceived by the Holy Ghost?
Was the Matt passage a physical fulfillment of the Isa 7 passage?
If one says yes to the above question, then one must address why they now feel God has shifted His method of operation and has began to fulfill prophecy not physically, but spiritually.
Is the prophecy of the government being on His shoulders found in Isa 9:6 being fulfilled spiritually now, or will it yet be fulfilled physically in the future when indeed the prophetic statement of vs 21 could be fulfilled?
If one feels the prophecy of Isa 9:6 is truly being fulfilled now in a spiritual manner, then does one really believe in the physical fulfillment of Isa 7, or was the virgin birth also a spiritual event?