I have always been taught that any time the Angel of the Lord showed up in the Old Testament it was pre-incarnate Jesus. But there’s another Angel of the Lord showing up to Joseph while Mary is pregnant with Jesus–who is this one?
From Matt. 1:20 we see that this angel is called “an angel of the Lord” By using “the angel of the Lord” in Matt. 1:24 the writer is indicating it’s the same angel. An angel of the Lord also appeared to Joseph after the Lord’s birth and warned him to take the family to Egypt (Matt. 2:13) and again in Matt. 2:19 to say it was safe to return to Israel.
Interpreting the phrase The Angel of the Lord as referring to a pre-incarnate appearance of Jesus is only appropriate for the Old Testament.