A.T. Robertson Commentary Matthew 2:22

"But when he heard that Archelaus was reigning over Judaea in the room of his father Herod, he was afraid to go thither; and being warned [of God] in a dream, he withdrew into the parts of Galilee," — Matthew 2:22 (ASV)

Warned in a dream (χρηματισθεις κατ' οναρ). He was already afraid to go to Judea because Archelaus was reigning (ruling, not technically king, βασιλευε). In a fret at last before his death Herod had changed his will again and put Archelaus, the worst of his living sons, in the place of Antipas. So Joseph went to Galilee. Matthew has had nothing about the previous dwelling of Joseph and Mary in Nazareth. We learn that from Luke who tells nothing of the flight into Egypt. The two narratives supplement one another and are in no sense contradictory.