But they had no child for Elisabeth was barren. They were now both elderly, at the time of life when naturally speaking it becomes hard or impossible for a couple to conceive, and yet this was going to be the time that God worked.
When God has a special purpose, he waits to work until all human powers have been exhausted, so that it is all the more obvious that what happens is the gift of God. All our greatest gifts and opportunities come from him. It was fitting that this greatest of prophets would be born by a birth that none could deny was supernatural.