Elizabeth and Zechariah were living in a town in the hill country of Judea when Mary went to visit them. Apparently, the Holy Spirit had told Elizabeth that Mary's child was the Messiah that the Jewish people had been waiting for because Elizabeth called Mary "the mother of my Lord" as she greeted her. Mary had not only been told that she was to have a child by the Holy Spirit, she was also told that her relative Elizabeth was going to have a child. As Mary was trying to comprehend all that was happening, Elizabeth's greeting must have strengthened her faith.
(Life Application Bible, New International Version, Tyndale House Publishers, Inc., Wheaton Illinois, and Zondervan Publishing House, Grand Rapids, Michigan, 1991, 1788.)