Luke 2:11

For there is born unto you this day in the city of David a Saviour, who is Christ the Lord.

Three titles of the Son of God were announced by the angels.

Saviour ... has reference to Jesus' office as the sin-bearer, the procurer of salvation for the sons of men, a salvation which, preeminently above everything else, was the remission of their sins and restoration of the fellowship lost in Eden.

Christ ... identifies Jesus as the fulfillment of Old Testament prophecy, the Shiloh, Anointed, Suffering Servant, and Messiah foretold of old. Although the term had been corrupted by the base and foreign elements of meaning imported into the title by the carnal and malignant secularism of the religious hierarchy, it had the true meaning that Jesus was the divine head of the theocracy, the lawful ruler of Israel, the promised Son of David who would usher in the great kingdom, misunderstood by the Jews as a mere resurrection of the low kingdom of Solomon.

The Lord ... The preference Luke showed for this title in his record of Jesus' life and teachings is alleged by the critics to have been the cause of his using it in such contexts as this, "retroactively," thus denying that Luke really reported here exactly what the angels said. Such a view is totally unworthy of acceptance. Rather, it is in the use of the term "Lord' by Elizabeth and by the angels, etc. which accounts for Luke's preference for it. This Gospel was written only thirty years after the events related; and the widespread use of "Lord" as a title of Jesus Christ, as evidenced by the writings and preaching of Paul, with whom Luke had been a traveling companion for many years, postulates that there was a cause for such widespread acceptance of the title; and that cause is evident in the event here, in which the angels of God called Jesus "Lord."