The Announcement of the Angel about the Birth of the Forerunner.
God through the Prophet Malachi foretold that before the advent in the world of Christ the Saviour Himself, there would have appeared the Forerunner, that is, the Predecessor of the Saviour. The Forerunner would be a great prophet; he would proclaim to the people the imminent appearance of Christ preparing them to meet Christ the Saviour.
For the birth of the Forerunner, God chose relatives of the Holy Virgin Mary, the priest Zacharias and his wife Elizabeth. Already old, they had no children. They fervently prayed to God to deliver them from such unhappiness.
One day, Zacharias was serving in the Temple in Jerusalem. When he entered the sanctuary for the censing, there appeared to him an angel of the Lord, standing on the right side of the table on which the incense was burning. Zacharias was confused; terror overcame him. The angel said to him, "Fear not, Zacharias, for your prayer is heard; and thy wife Elizabeth shall bear thee a son, and thou shalt call his name John. And thou shalt have joy and gladness..., for he shall be great in the sight of the Lord..., and he shall be filled with the Holy Spirit even from his mother’s womb. And many of the children of Israel shall he turn to the Lord their God." He would come first; that is, he would be the Forerunner before the Lord the Saviour. "And he shall go before Him in the spirit and power of Elijah... to make ready a people prepared for the Lord." Zacharias overwhelmed with joy, could not believe immediately, and said, "How shall I know this? For I am an old man and my wife well stricken in years." The angel answering said, "I am Gabriel that stand in the presence of God and am sent to speak unto thee... behold, thou shalt be dumb and not able to speak until the day that these things shall be performed because thou believest not my words."
In the meantime, the praying people awaited Zacharias and were amazed that he delayed so long in the sanctuary of the Temple. Coming out, he was unable to speak with the people, explaining with signs. Then, everyone understood that he had experienced a vision in the sanctuary. At the end of his services for the day in the Temple, Zacharias went home.
When Elizabeth found out about the great favour God was bestowing on them, she hid her joy from people with humility and thanked God.
Note: This sacred event is described in the Holy Gospels by the Apostle and Evangelist Luke (Luke 1:5-25).