Luke 1:67

And his father Zacharias was filled with the Holy Ghost,
&c.] With a spirit of prophecy, as his wife Elisabeth had been before, ( Luke 1:41 )

and prophesied
saying; the following things, relating to the Messiah, his incarnation and redemption by him; to the accomplishing of the covenant, oath, promise and mercy of God to his people; and to his son, the forerunner of Christ; and to his work and office, in the various parts and branches of it, which he should perform. Whence it appears, that the following song is of divine inspiration; and that Zacharias spake it as he was moved by the Holy Ghost, as the prophets of old did.