And the angel… said to her, “The Holy Spirit will come upon you, and the power of the Highest will overshadow you; therefore… that Holy One who is to be born will be called the Son of God.”
Jesus was “Son of God”. Sometimes we so emphasize Jesus’ earthly life that we forget He is also God. Jesus’ actions were radical for a human, but imagine God serving as Jesus did – scandalous! Why do you suppose the angel gave Mary this message before Jesus was born? Why was it important for her to know Jesus would be called “Son of God”?