XVI. These I call by name (for they are not nameless like the stars which are numbered and have names), and they follow me, for I rear them up beside the waters of rest; and they follow every such shepherd, whose voice they love to hear, as you see; but a stranger they will not follow, but will flee from him, because they have a habit of distinguishing the voice of their own from that of strangers. They will flee from Valentinus with his division of one into two, refusing to believe that the Creator is other than the Good. They will flee from Depth and Silence, and the mythical Æons, that are verily worthy of Depth and Silence. They will flee from Marcion's god, compounded of elements and numbers; from Montanus' evil and feminine spirit; from the matter and darkness of Manes; from Novatus' boasting and wordy assumption of purity; from the analysis and confusion of Sabellius, and if I may use the expression, his absorption, contracting the Three into One, instead of defining the One in Three Personalities; from the difference of natures taught by Arius and his followers, and their new Judaism, confining the Godhead to the Unbegotten; from Photinus earthly Christ, who took his beginning from Mary. But they worship the Father and the Son and the Holy Ghost, One Godhead; God the Father, God the Son and (do not be angry) God the Holy Ghost, One Nature in Three Personalities, intellectual, perfect, Self-existent, numerically separate, but not separate in Godhead.
XVII. These words let everyone who threatens me today concede to me; the rest let whoever will claim. The Father will not endure to be deprived of the Son, nor the Son of the Holy Ghost. Yet that must happen if They are confined to time, and are created Beings...for that which is created is not God. Neither will I bear to be deprived of my consecration; One Lord, One Faith, One Baptism. If this be cancelled, from whom shall I get a second? What say you, you who destroy Baptism or repeat it? Can a man be spiritual without the Spirit? Has he a share in the Spirit who does not honour the Spirit? Can he honour Him who is baptized into a creature and a fellow-servant? It is not so; it is not so; for all your talk. I will not play You false, O Unoriginate Father, or You O Only-begotten Word, or You O Holy Ghost. I know Whom I have confessed, and whom I have renounced, and to Whom I have joined myself. I will not allow myself, after having been taught the words of the faithful, to learn also those of the unfaithful; to confess the truth, and then range myself with falsehood; to come down for consecration and to go back even less hallowed; having been baptised that I might live, to be killed by the water, like infants who die in the very birthpangs, and receive death simultaneously with birth. Why make me at once blessed and wretched, newly enlightened and unenlightened, Divine and godless, that I may make shipwreck even of the hope of regeneration? A few words will suffice. Remember your confession. Into what were you baptised? The Father? Good but Jewish still. The Son?...good...but not yet perfect. The Holy Ghost?...Very good...this is perfect. Now was it into these simply, or some common name of Them? The latter. And what was the common Name? Why, God. In this common Name believe, and ride on prosperously and reign, and pass on from hence into the Bliss of Heaven. And that is, as I think, the more distinct apprehension of These; to which may we all come, in the same Christ our God, to Whom be the glory and the might, with the Unoriginate Father, and the Lifegiving Spirit, now and for ever and to ages of ages. Amen.
Source: Orations (New Advent)