The nativity mystery "conceived from the Holy Spirit and born from the Virgin Mary", means, that God became human, truly human out of his own grace. The miracle of the existence of Jesus , his "climbing down of God" is: Holy Spirit and Virgin Mary! Here is a human being, the Virgin Mary, and as he comes from God, Jesus comes also from this human being. Born of the Virgin Mary means a human origin for God. Jesus Christ is not only truly God, he is human like every one of us. He is human without limitation. He is not only similar to us, he is like us.