The reason we can state this as an article of faith is because Jesus entered into our world and married Himself into our humanity. In her the divinity of God the Son became our humanity in Jesus, born of Mary in Nazareth, an event that happened in real time, in real history, on our planet and in our world. Because of her, the glory of God became human flesh. Because of Mary, our humanity entered into the glory of divinity, the glory of God. Human rebellion, however, is at work as always.
Evil is always at work in the presence of goodness.
Evil is always attempting to corrupt goodness, to reduce it and minimize it, to seduce and change it. Evil is the disfigurement of good. Forces instantly go to work to attempt to minimize and diminish it, to attempt to seduce it and quash it. In the story of Mary, the mother of Jesus and our mother, is the story of the Woman, the Child, and the Dragon. It's a story of creation, of birthing, of life.