Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
While Zacharias ministered at the golden altar of incense in the holy place, it was announced to him by the angel Gabriel that his wife Elisabeth, who was also of a priestly family, now stricken in years, would give birth to a son who was to be called John, and that he would be the forerunner of the long-expected Messiah (Lk. 1:12-17). As a punishment for his refusing to believe this message, he was struck dumb and "not able to speak until the day that these things should be performed" (1:20). Nine months passed away, and Elisabeth's child was born, and when in answer to their inquiry Zacharias wrote on a "writing tablet," "His name is John," his mouth was opened, and he praised God (1:60-79). The child (John the Baptist), thus "born out of due time," "waxed strong in spirit" (1:80).