Longer Catechism (Orthodox) 10.243

Chapter 10 — Part I — Article VIII (Of the Holy Ghost)

Section 243. Q. Whence does it appear that the Holy Ghost is equally with the Father and the Son, and, together with them, to be worshiped and glorified? A. It appears from this, that Jesus Christ commanded to baptize in the name of the Father, and of the Son, and of the Holy Ghost. Matt. xxviii. 19.