In this talk, Sr. Magdalene will speak about Trinitarian monotheism, the eternal vs. temporal processions, the eternal procession of the Son as generation, and the eternal procession of the Holy Spirit as common spiration. She will also explain the heresies of Arianism and Sabellianism, and their common error of taking the eternal processions to be outward acts, rather than interior to God himself. Aquinas points out their mistake and emphasizes the interiority of the divine processions.