The mission of John

 Luke 1:76–79 (NRSV)

76And you, child, will be called the prophet of the Most High; for you will go before the Lord to prepare his ways,
77to give knowledge of salvation to his people by the forgiveness of their sins.
78By the tender mercy of our God, the dawn from on high will break upon us,
79to give light to those who sit in darkness and in the shadow of death, to guide our feet into the way of peace.”

John was conceived through the supernatural intervention of God that overcame the sterility of Elizabeth. Both she and her husband Zacharias were old and beyond childbearing years. Yet God did the impossible by enabling them to conceive and give birth to John who would be the forerunner of Jesus. He had a great mission to accomplish, and his life needed to be separated from negative physical things that could corrupt his identity and cause people to doubt his messages. God set him aside to fulfill his mission to prepare the way for the ministry of Jesus. His message to the people brought hope of forgiveness and salvation that they had been promised and waiting for throughout many years. The 400 previous years were times when no prophetic words were given to the people. They were in spiritual darkness, but everything would change when John began his ministry. God had a perfect plan, and he would accomplish it through his supernatural intervention in the birth of John and Jesus.