Compare 4Q246 2:1 and Luke 1:31

"... The concept of the "Son of God," a designation that is strongly associated with Jesus as Messiah in Christian theology, is referred to in a Dead Sea Scroll text called 4Q246 (or the Aramaic Apocalypse), written in Aramaic and dating to about the turn of the era ... This text contains a remarkable parallel to the Annunciation scene in Luke, in which the angel Gabriel appears to the Virgin Mary to announce the conception of Jesus ... Both texts maintain that he "will be great," he will be called the "Son of the Most High," he will be called "the Son of God," and his kingdom will be everlasting ..."

"... This opens up the possibility that pre-Christian Judaism might already have sometimes thought of the Davidic messiah as God's son. The possibility is enhanced by an intriguing fragment from the Dead Sea Scrolls designated 4Q246 ... Unfortunately, the text, as said, is fragmentary, and this disallows a certain identification of the figure who is called "Son of God" and "Son of the Most High." Some have suggested he should be identified with an historical king of Israel, others with an Antichrist figure, still others that the Son of God is the angel, Michael, in his eschatological role. But many have instead given the text a messianic sense: the Son of God is the Messiah. The arguments in favor of this position cannot be marshaled here, but they should probably carry the day. One reason is the very close parallel in Luke: "He will be great, and will be called the Son of the Most High, and the Lord God will give to him the throne of his ancestor David. He will reign over the house of Jacob forever, and of his kingdom there will be no end" (1:32-33). This, as has often been observed, is striking close to 4Q246, and it is a prophecy of the Messiah, Jesus. So while certainty eludes us, the Dead Sea Scrolls have given us additional reason to suspect that, among its other associations in a Jewish context, the title "Son of God" might very well have had royal messianic connotations ..."