Roman Catechism 10.8

Chapter 10 — Part I: The Creed — Article VIII: I Believe in the Holy Ghost

Section 8. The Holy Ghost Is Equal To The Father And The Son — The people, when once acquainted with the meaning of His name, should first of all be taught that the Holy Ghost is equally God with the Father and the Son, equally omnipotent and eternal, infinitely perfect, the supreme good, infinitely wise, and of the same nature as the Father and the Son.