39 For the Word of God did not assume a feigned and unsubstantial body, as already in the first century of Christianity some heretics declared and who were condemned in these solemn words of St. John the Apostle: "For many seducers are gone out into the world, who do confess not that Jesus Christ is come in the flesh. Here is a seducer and the antichrist,"(35) but He united to His divine Person a truly human nature, individual, whole and perfect, which was conceived in the most pure womb of the Virgin Mary by the power of the Holy Ghost.(36)
Source: Haurietis Aquas (Vatican.va)