Here’s the rub — was Mary worthy to carry our Lord? Was there something innate in her which made her the only woman ever born who might carry the Christ? Not necessarily so. Mary finds favor with God. God chooses to bless Mary; and Mary believes and accepts the blessing. Mary has done nothing that we know of which qualifies her to carry Jesus except that she is betrothed to Joseph, a man from the house of David and that she is a virgin and that she lives in Nazareth.
Mary is not sinless. She is not born free of sin. However, Mary is the first Christian. She accepts her son as the Son of God and as her Messiah when Gabriel speaks to her. She accepts that she is to name her child Jesus and that He “will be called holy.” She does not fully comprehend all that is to be, but she gives herself to Her son before He is born. (Luke 1: 35)
When Mary greets Elizabeth, “the baby leaps in her womb. And Elizabeth is filled with the Holy Spirit.” (Luke 1: 41) Elizabeth shouts “with a loud cry, ‘Blessed are you among women, and blessed is the fruit of your womb! And blessed is she who believed that there would be a fulfillment of what was spoken to her from the Lord.” (Luke 1: 42, 45)
God’s sovereign blessing and Mary’s belief are what qualify her to carry Christ.