Part 1, Section 2, Chapter 2, Article 3, Paragraph 2, SubSection 2, Heading 5
497 The Gospel accounts understand the virginal conception of Jesus as a divine work that surpasses all human understanding and possibility: 148 "That which is conceived in her is of the Holy Spirit", said the angel to Joseph about Mary his fiancee. 149 The Church sees here the fulfilment of the divine promise given through the prophet Isaiah: "Behold, a virgin shall conceive and bear a son." 150