This hymn surveys God's plan through the forerunner and the anointed Davidic heir. The Lord, the God of Israel, is blessed for how he works through these two major agents. Where Mary's hymn was cosmic and personal, Zechariah's is cosmic and universal. Zechariah rejoices that God has raised up the Davidic horn to do his work of deliverance, as well as sending a prophet to prepare the way for him. That deliverance possesses both political and spiritual dimensions, as verses 71-75 and 78-79 show.
Luke describes the hymn as Spirit-inspired. In other Lukan accounts, often the Spirit's presence leads to a prophetic declaration or to praise (Acts 2:17-18; 11:27; 13:1; 19:6; 21:9). This hymn offers a divine commentary on God's plan. John is the prophet of the Most High pointing to Jesus, the bright Morning Star. So Zechariah highlights Jesus just as his son John will.