What a marvelous scene it must have been–John, yet within his mother’s womb, filled with the Holy Ghost and leaping for joy in an unspoken testimony of the divine sonship of the unborn child that Mary carried; Elisabeth greeting her cousin Mary in the spirit of prophecy and Mary responding by that same spirit. Again we are compelled to say, how perfect! The testimony of two women: the aged Elisabeth and the youthful Mary; each bearing a child conceived under miraculous circumstances, rejoicing together.
As Jesus Christ was born the rightful heir to David’s kingdom, so John was born the rightful heir to the office of Elias that he had been promised by Gabriel. Robert J. Matthews identifies that heirship in this language:
The things of the law of Moses, especially with regards to the qualifications to the priests and their functions in the offerings of various animal sacrifices, were designed by revelation to prefigure and typify the Messiah and to bear witness of him. Heavy penalties were affixed to the performance of sacred rites and duties without the proper authority. It was, therefore, essential that when the Messiah came in person as the Lamb of God, John, the forerunner and witness of the Lamb, should be of the proper lineage to qualify for the mission. If it was necessary for a priest to be of the lineage of Aaron in order to labor with the sacrificial symbols, which were only prefigures of the Messiah, how much greater the necessity that John, the forerunner of the Messiah in person, be of the proper priestly lineage and authority.
Sperry Symposium Classics, Joseph Fielding McConkie, 2006, Brigham Young University & Deseret Book, 111-112.