from a treatise:
Our Lord commanded us to baptize in the name of the Father, and of the Son, and of the Holy Spirit. In baptism, then, we profess faith in the Creator, in the only begotten Son, and in the gift which is the Spirit.
There is one creator of all things, for in God there is one Father from whom all things have their being. And there is one only-begotten Son, our Lord Jesus Christ; through him all things exist. And there is one Sprit, the gift who is in all.
So all follow their due order, according to the proper operation of each: One power, which brings all things into being; One son, through whom all things come to be; and one gift of perfect hope.
Nothing is wanting to this flawless union. In Trinity, there is infinity of endless being, perfect reflection of the divine image, and mutual enjoyment of the gift.