The privilege of giving birth to the Savior of the world couldn’t be given to just anyone. Only a woman with outstanding faith, an extraordinary character, and pure heart would be appropriate for such an honor.
We find information about Mary’s beautiful character (Luke 1:26-56) in the book of Luke, when she responds to the news from the angel Gabriel that Mary would give birth to the most important child in the world. 
Mary had humility – she was not full of pride. When Gabriel told her that she was highly favored by God, she was troubled and confused. If she was prideful, she may have immediately rejoiced and wonder how she might benefit from being told she was in favor.
After the shock of this surprising news, she thoughtfully and intelligently asked how it would occur. Once told, she said in Luke (1:38, Life Application Bible), “I am the Lord’s servant, and I am willing to accept whatever He wants.”
What a humble and appropriate response to this unusual but wonderful experience!
Since Mary loved and respected God, she quickly decided to accept God's plan for her life no matter how it might look to others. She had faith in God and trusted Him to work things out even though she did not have all of the information.
Mary’s cousin, Elizabeth, was also going to have a son who would grow up to be John the Baptist. Elizabeth recognized Mary’s strong faith when she told her in Luke, (Luke 1:45, Life Application Bible), “You are blessed because you believed the Lord would do what he said.”
Mary went on to rejoice in God, calling him mighty and merciful, while acknowledging her low status. She then discussed some of Israel’s history, showing she was an intelligent and careful student.  
So, why was Mary chosen to be the mother of God’s son, Jesus? Because of her strong faith, humility, trust in God, and extraordinary character. She submitted to God’s will even under seemingly impossible circumstances and readily agreed to follow God’s will for her life, whatever it would be.

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