From the LCMS website:
Zechariah and Elizabeth were “righteous before God, living blamelessly according to all the commandments and regulations of the Lord” (Lk 1:6). Zechariah, a priest in the Jerusalem temple, was greeted by the angel Gabriel who announced that Zechariah and Elizabeth would become parents of a son. Initially Zechariah did not believe Gabriel’s announcement because of their old age. For his disbelieve, Zechariah became unable to speak. After their son was born, Elizabeth named her son John. Zechariah confirmed his wife’s choice and his ability to speak was restored. In response, he sang the Benedictus, a magnificent summary of God’s promises in the Old Testament and a prediction of John’s work as forerunner to Jesus (Lk. 1:68–79). Zechariah and Elizabeth are remembered as examples of faithfulness and piety.