... the challenge of not reading more into the narratives than are there, and the challenge of thinking twice before harmonizing Matthew and Luke's narratives. Technically harmonization is possible, but, as Doug Chaplin at Clayboy observes, the cost may be that we become less 'biblical' rather than more 'biblical' by doing so.
Here is an excerpt from his thoughtful post, Ox and ass and we three kings: Christmas harmonies and evangelical humbug:
"Historically speaking, the main problem with Matthew’s story is Luke’s story, and vice versa. They can be harmonised only by careful suppression of each’s specificity. In Matthew the holy family home is always in Bethlehem. In Luke, they travel directly home to Nazareth after the forty days of Mary’s purification are up. One could go on, but the problem of historical believability is not just an issue for modern sceptics rejecting God’s work – it’s a problem of two contradictory and different narratives.
This historical use of the text is one thing. Preaching is another, and here there are at least two ways of preaching the Christmas story. The first is the one that pays attention to the text, that doesn’t harmonise the accounts, or fit the shepherds and the magi together. In this version it’s appropriate (in Year C – when Luke is the gospel?) to be sceptical about an inn and explore the idea of a guest room. It’s appropriate (in year A – when we read Matthew?) to consider Herod’s bloodthirsty reputation and the irony of astrology guiding pagans to worship, while those who have the prophecies of Scripture use them only to kill. That is a perfectly appropriate and legitimate use of Scripture in preaching, and one where my head and heart unite. I guess on that people of many views can agree."
With respect to separating Matthew and Luke, I would add the small point missed by many Anglicans of my acquaintance: the wise men should only be introduced to the preaching calendar at Epiphany (6 January)!