Luke 2:39 So when Joseph and Mary had performed everything according to the law of the Lord, they returned to Galilee, to their own town of Nazareth.

This statement is held to be at variance with that of Matthew, which implies that they resided in Bethlehem for some months after the birth of Jesus (i.e. until the visit of the Magi) and states (Mt 2:14) that they then took Jesus to Egypt.

Gundry (Commentary on Matthew) argues partly on linguistic grounds:

‘Luke says that the Holy Family went back to Nazareth when they finished the ceremonies in the Temple (Luke 2:39), i.e., forty days after Jesus’ birth (Leviticus 12). This statement leaves no room for the Slaughter of the Innocents, the flight to Egypt, and the residence there till the death of Herod. In its other fifty-nine occurrences throughout Luke-Acts, does not allow for gaps like that. On the contrary, it draws temporal connections so close that we often need to translate it “while, as.”‘

James McGrath (The A – Z of the New Testament) supposes that Matthew and Luke give mutually incompatible accounts:

‘After Jesus was born, within two months he was in Jerusalem, according to Luke, who says that once they had done all that was required, they returned to Nazareth, which in Luke is their hometown. There is no room for a relocation to Bethlehem for Jesus to be there at age two, as depicted in Matthew. Luke’s story is simply a different one, with a different timeline from Matthew’s.’

But there is nothing implausible about the historicity of an intervening journey to Egypt, given that Matthew and Luke each offer independent and highly selective accounts.

Blomberg notes that

‘the next two verses in Luke summarize twelve years, a period of time much longer than we would suspect if it weren’t for verse 42 specifying the interval. More dramatically still, Lk 2:52 refers to a period of about eighteen years, as Lk 3:23 discloses, as Luke jumps from the twelve-year-old boy Jesus to his life as a man at about the age of thirty. When we recall, however, that ancient biographers often skipped over large, comparatively unimportant stretches of their subjects’ lives, this should not surprise us.’

(The Historical Reliability of the New Testament)

Blomberg adds:

‘Nor should we assume there is a contradiction between their being guided to Nazareth, which Matthew does not mention until Mt 2: 22– 23, and Luke’s record of their returning to their original home (Lk 2: 39).  It appears likely that they initially planned to resettle in Bethlehem because the Magi find them living in a home there, possibly up to two years after Jesus’s birth (Mt 2: 11, 16), no doubt to avoid the stigma and ostracism that would have constantly surrounded them in tiny Nazareth.  But, when Herod’s orders to kill the babies in and around Jerusalem forced them to flee and when they learned that the worst of his sons, Archelaus, was ruling in Judea after his death, it was clearly better to suffer some social discomfort back in Galilee than to risk the child’s life again.’

Peter J. Williams explains why it may have been a perfectly plausible editorial decision on Luke’s part to omit this episode:

‘First, it’s important to note that the flight to Egypt need not have been for long. The key thing would have been to get outside Herod’s jurisdiction. To do this they might have gone 200 miles to Pelusium or merely to Ostracine, which was 65 miles closer. Luke’s description of Mary and Joseph’s return to Nazareth after Jesus’ birth in Lk 2:39 reads: “When they had finished everything according to the law of the Lord, they returned to Galilee, to their town of Nazareth” (NTE). While it doesn’t mention the events of Matthew 2:13-18, it doesn’t contradict these verses either.

‘What if we were to consider a hypothetically rewritten version, as follows? “And when they had finished everything according to the law of the Lord, they went down to Egypt and then returned to Galilee, to their town of Nazareth.” Automatically our attention would be focused on the question of why they went to Egypt. In fact, Luke would have to refocus his narrative in major ways even to make sense of this additional journey. In other words, the objection to Luke’s omission of Egypt is really an insistence that there can be no such thing as précis or authorial selectivity, and that Luke must mention everything significant from Matthew. It’s an approach that is in tension with having multiple accounts in the first place.’

Bock (in Holman Apologetics Commentary) notes that the flight to Egypt suits the general character of Matthew’s Gospel:

‘Matthew, whose target audience was primarily Jewish, chose to highlight the trip to Egypt because to Jews the fact that Jesus recapitulated the history of Israel by going to and returning from Egypt is important. This fact was not so relevant to Luke’s Gentile audience, so his narration focused on where Jesus ended up living for most of his childhood and left Egypt unmentioned. Thus readers may be reading too much into Luke if they take his narrative (Lk 2:39) to mean that Mary, Joseph, and baby Jesus settled down in Nazareth immediately after they presented Jesus at the temple. Luke may have simply telescoped to a later event.’

What should we make of the proposal that Luke simply didn’t know about the journey to Egypt?  In view of the highly selective nature of the Gospels, I tend to be a bit sniffy when writers claim that such-and-such a Gospel writer ‘knows nothing’ of a certain episode in Jesus’ life.  In the present case, however, I think that it is reasonable to suggest that Luke simply didn’t know about the flight in the Egypt.  That would be a reasonable inference from what he writes here.  After all, apart from what Luke records in the closing verses of the present chapter, both he and the other Evangelists ‘know nothing’ about Jesus’ childhood and adolescence.

It is unlikely that Matthew and Luke had access to one another’s accounts.

Jonathan McClatchie surmises that Luke has made an undestandable, but mistaken, assumption based on the information he has been given:

‘The text strongly implies that it was very shortly after the purification that they returned home, whereas Matthew strongly indicates that Jesus’ family remained in Bethlehem for some considerable time after Jesus’ birth and only returned to Nazareth following the flight to Egypt. One might explain this apparent discrepancy? Personally, I think that the explanation that makes the most sense is that Luke’s sources (which may have been written, oral, or a combination of the two) did not contain an account of the coming of the magi, the slaughter of the children in Bethlehem, or the flight to Egypt. I think plausibly Luke’s principle source for his nativity account was Mary. It is a reasonable conjecture that Mary may have told Luke the story of Simeon and Anna in the temple (Lk 2:25-38) before transitioning to the next account by saying something like “And later, when we were living in Nazareth we used to come every year to Jerusalem to the Passover feast.” Perhaps Luke made the natural assumption that they had returned to Nazareth immediately following the presentation at the temple, and thus wrote a transition connecting the two accounts.’

Ian Paul, while agreeing that a temporal reference (‘When Joseph and Mary had done everything required by the law…’) is the most natural reading, notes that:

‘the Greek phrase kai hos can have a range of meanings; the emphasis for Luke here is that, since they had done everything, they were able to leave, contributing to Luke’s consistent theme throughout the early chapters that Joseph and Mary, along with other characters in the story, are obedient, Torah-observant, pious Jews.’