This came to pass fifteen months before the birth of Christ, after the vision of the Angel that Zacharias, the father of the Forerunner, saw in the Temple while he executed the priest’s office in the order of his course during the feast of the Tabernacles, as tradition bears witness. In this vision, the Archangel Gabriel appeared to Zacharias and said to him, “Thy prayer is heard; and thy wife Elizabeth shall bear thee a son, and thou shalt call his name John” (Luke 1:13). Knowing that Elizabeth was barren, and that both he and she were elderly, Zacharias did not believe what the Angel told him, although he had before him the example of Abraham and Sarah, of Hannah, mother of the Prophet Samuel, and of other barren women in Israel who gave birth by the power of God. Hence, he was condemned by the Archangel to remain speechless until the fulfilment of these words in their season, which also came to pass (Luke 1:7-24).
Apolytikion in the Fourth Tone
Rejoice, O thou barren one who hadst not borne until now; for lo, in all truth thou hast conceived the lamp of the Sun, and he shall send forth his light over all the earth, which is afflicted with blindness. Dance, O Zacharias, and cry out with great boldness: The one to be born is the blest Prophet of God Most High.
Kontakion in the First Tone
Great Zacharias now doth rejoice with resplendence; Elizabeth his glorious yoke-mate exulteth; for she hath conceived divine John the Forerunner worthily, whom the great Archangel had announced with rejoicing, whom, as it is meet, we men revere as a sacred initiate of grace divine.
From www.goarch.org