to Kunigunde Kreuzerin,
Mary ‘bore a son’ (έτεκεν υίόν, Mt. 1.25; Lk. 2.7).
OK, but is it enough to say "Luke" copied the phrase from gMatthew? "Luke" used the phrase at the birth of Jesus but "Matthew" put it well before that.
It was in Bethlehem of Judaea, as Micah had foretold (Mt. 2.1, 5f), and Matthew turns the citation in line with the prophecy to David, ‘You shall be shepherd of my people Israel’ (v. 6d, 2 Sam. 5.2); Luke says that Joseph went up to Judaea to the city of David which is called Bethlehem, being of Davidic ancestry, and Mary with him (2.4).
If "Luke" knew about gMatthew, she would have Mary & Joseph living in Bethlehem (as implied in gMatthew). That would have avoided her to have a very pregnant Mary going to Bethlehem from Nazareth for no reason at all, with Joseph, not even Mary's husband. And Joseph going there "because he was of the house and lineage of David", which does not make sense. And in the OT, it is Jerusalem, not Bethlehem, being the city of David.
In Matthew God brings a company of strangers, magi, leading them by a star rising in the sky; in Luke God brings a company of strangers, shepherds, summoning them by his angel, and the multitude of the heavenly host.
"a star rising in the sky" is not "a multitude of the heavenly host".
The structure of the two nativity stories, even with the similarities, is very normal and even predictable: Because of some prophecies, Jesus as the Son of David, had to be born in Bethlehem. But his advent could not be "secret" and only witnessed by Mary & Joseph, as some parents being on their own in a remote place. So the baby Jesus had to be seen by others, with fanfare and divine intervention. That makes baby Jesus exceptional.
When the magi saw the star, they rejoiced with exceeding great joy (έχάρησαν χαράν μεγάλην σφόδρα, 2.10); the angel brought the shepherds good news of χαράν μεγάλην for all the people (2.10).
"χαράν μεγάλην" appears also in Lk 24:52 and Acts 15:3. So the phrase was part of "Luke" vocabulary, with no need to have been copied from gMatthew.
The magi come and see the child (τό παιδίον) with Mary his mother, and fall before him (‘when you have found him’, said Herod). The shepherds came with haste and found Mary and Joseph and the baby laid in the manger; and when they had seen, they made known the saying told them of the child (του παιδιού τούτου, 2.17).
"παιδίον" (young child, boy or girl) is widely used in gLuke (13 times) and gMark (11 times). No need for "Luke" to pick up the word from gMatthew.
Magi and shepherds close the scene by returning whence they had come; and Luke then notes that ‘his name was called Jesus’ at his circumcision, just as Matthew says that Joseph called his name Jesus (1.25).
If "Luke" knew gMatthew (1:25 ἐκάλεσεν τὸ ὄνομα), she would have Jesus named by the angel well before Jesus was born. However, in Lk 2:21, Jesus is named (κληθὲν) by the angel prior to Joseph at the circumcision (ἐκλήθη τὸ ὄνομα). So we have, as named by an angel "ἐκάλεσεν τὸ ὄνομα" <=> "κληθὲν".
Finally, "Luke" did not give a time slot for gMatthew having the threesome going to Egypt, staying there for a while and then coming back.
It does not look here "Luke" knew about gMatthew.
Cordially, Bernard