He replied, “The Holy Spirit will come upon you, and the power of the Most High will cover you. The baby who is to be born is holy, and will be called the Son of God.
During the time when Herod was king of Judea, there was a priest called Zechariah, who came from the Abijah priestly division. He was married to Elizabeth, who was also descended from Aaron the priest.
By her trust in God even Sarah herself was given the ability to conceive a child though she was too old, because she trusted God who had made the promise.