The Spirit then being established in us, [in baptism] the Son and the Father come; and they make their dwelling in us. For the Trinity is indivisible, and its Godhead is one; and there is one God overall and through all, and in all. This is the faith of the Catholic Church; for on the Trinity the Lord founded it and rooted it, when He said to His disciples, “Go out and instruct every people, baptizing them in the name of the Father and of the Son and of the Holy Spirt.”

                                                  Saint Athanasius