On The Holy Trinity

12. The Holy Spirit, then, is also said to be sent, on account of these corporeal forms which came into existence in time, in order to signify and manifest Him, as He must needs be manifested, to human senses; yet He is not said to be less than the Father, as the Son, because He was in the form of a servant, is said to be; because that form of a servant inhered in the unity of the person of the Son, but those corporeal forms appeared for a time, in order to show what was necessary to be shown, and then ceased to be. Why, then, is not the Father also said to be sent, through those corporeal forms, the fire of the bush, and the pillar of cloud or of fire, and the lightnings in the mount, and whatever other things of the kind appeared at that time, when (as we have learned from Scripture testimony) He spake face to face with the fathers, if He Himself was manifested by those modes and forms of the creature, as exhibited and presented corporeally to human sight? But if the Son was manifested by them, why is He said to be sent so long after, when He was made of a woman, as the apostle says, "But when the fullness of time was come, God sent forth His Son, made of a woman," [260] seeing that He was sent also before, when He appeared to the fathers by those changeable forms of the creature? Or if He cannot rightly be said to be sent, unless when the Word was made flesh, why is the Holy Spirit said to be sent, of whom no such incarnation was ever wrought? But if by those visible things, which are put before us in the Law and in the prophets, neither the Father nor the Son but the Holy Spirit was manifested, why also is He said to be sent now, when He was sent also before after these modes?

13. In the perplexity of this inquiry, the Lord helping us, we must ask, first, whether the Father, or the Son, or the Holy Spirit; or whether, sometimes the Father, sometimes the Son, sometimes the Holy Spirit; or whether it was without any distinction of persons, in such way as the one and only God is spoken of, that is, that the Trinity itself appeared to the Fathers by those forms of the creature. Next, whichever of these alternatives shall have been found or thought true, whether for this purpose only the creature was fashioned, wherein God, as He judged it suitable at that time, should be shown to human sight; or whether angels, who already existed, were so sent, as to speak in the person of God, taking a corporeal form from the corporeal creature, for the purpose of their ministry, as each had need; or else, according to the power the Creator has given them, changing and converting their own body itself, to which they are not subject, but govern it as subject to themselves, into whatever appearances they would that were suited and apt to their several actions. Lastly, we shall discern that which it was our purpose to ask, viz. whether the Son and the Holy Spirit were also sent before; and, if they were so sent, what difference there is between that sending, and the one which we read of in the Gospel; or whether in truth neither of them were sent, except when either the Son was made of the Virgin Mary, or the Holy Spirit appeared in a visible form, whether in the dove or in tongues of fire.