If all we had were the Old and the New Testament and no other Jewish literature, the fact that Gabriel calls Jesus “the Son of the Most High” and “Son of God” would seem incidental. We might think that these epithets are allusions to Psalm 2 or to the promise to the house of David in 2 Samuel 7. But there would be no reason to assume that these are specific titles that have any particular significance beyond these references to the Old Testament.
