Roman Catechism 7.9

Chapter 7 — Part I: The Creed — Article V: He Descended into Hell; the Third Day He Rose Again from the Dead

Section 9. "He Descended" — We are not to imagine that His power and virtue only, and not also His soul, descended into hell; but we are firmly to believe that His soul itself, really and substantially, descended thither, according to this conclusive testimony of David: Thou wilt not leave my soul in hell.