We find ourselves speaking almost inevitably of 1st, 2d, and 3d persons; thus implying some order in the persons. No orthodox Christian, of course, understands this order as relating to a priority of time, or of essential dignity. To what, then, does it relate? And is there any substantial reason for assigning such an order at all? We reply: There must be; when we find that where the three persons are mentioned by Scripture, in connection, as in Matt. xxviii:19, &c., &c., they are usually mentioned as Father, Son, and Holy Ghost, and not in reversed order; that in all allusions to the properties and relations of the three, the Father is always spoken of (e.g. the word Father) by some term or trait implying primary rank, and the other two, by some implying secondariness; as Christ is His Son, the Holy Ghost His Spirit; they are sent, He the Sender; and in their working, there is always a sort of reference to the Father’s primariness, (if I may coin a word,) directing their operation. See also Jno. v; 26; x:38; xiv:11; xvii:21; Heb. i:3.
But if it be asked, what is the primariness, the answer is not so easy. It was the usual answer of the ante-Nicene, and especially the Greek Fathers, that it indicated the order of derivation, that the personality of the Son is from that of the Father, not the Father’s from the Son; and so of the Holy Ghost. (And so far, it must be allowed, the fair force of the Scripture facts just stated, carries them properly enough.) The Father they regarded as anaitios, as pege theou, or arche theou, the Son and Holy Ghost as aitiaitoi, theoi ek theou, and as deriving their personal subsistence from the eternal act of the Father in communicating the divine essence to them in those modes of subsistence. And this view was embodied in both forms of the Nicene Creed, of A.D. 325 and 381, where the Son is called, “God of God, Light of Light, and very God of very God;” language never applied to the Father as to the Son. Their idea is, that the Father, the original Godhead, eternally generates the person, not the substance of the Son, and produces by procession the person, not the substance of the Holy Ghost, by inscrutably communicating the whole indivisible divine substance, essentially identical with Himself in these two modes of subsistence; thus eternally causing the two persons, by causing the two additional modes of subsistence. This statement, they suppose, was virtually implied in the very relation of terms, Father and His Son, Father and His pneuma, by the primariness of order always assigned to the Father, and by the distinction in the order of working. And they relied upon this view to vindicate the doctrine of the Trinity from the charge of tritheism.
Was it objected, that they represented the 2d and 3d persons as beginning to exist, and thus robbed them of a true self-existence and eternity? These Fathers could answer with justice: No; the processes of personal derivation were eternal, immanent processes, and the Father has a personal priority, not in time, but only in causation; e.g. the sun’s rays have existed precisely as long as he has; yet the rays are from the sun and not the sun from the rays. And the 2d. person may be derived as to His personality, thoes ek theou, and yet self-existent God; because His essence is the one self-existent essence, and it is only His personality which is derived. They regard self-existence as an attribute of essence, not of person.
Was it objected that these derived personalities were unequal to the 1st person? They answer: No; because the Father put His whole essence in the two other modes of subsistence. Was it said, that then the personal subsistence of the 2d. and 3d. was dependent on the good pleasure of the 1st.; and therefore, revocable at His pleasure? They answered, that the generation and procession were not free, contingent acts, but necessary and essential acts, free indeed, yet necessitated by the very perfection of the eternal substance. You will perceive that I have not used the word subordination, but derivation, to express this personal relation. If you ask me whether I adopt the Patristic view, thus cleared, as my own, I reply, that there seems to me nothing in it inconsistent with revealed truth; yet it seems to me rather a rational explanation of revealed facts, than a revealed fact itself.
~Lectures in Systematic Theology pg. 204
Dabney is here a better historical source than Hodge and Warfield, and though he might lament the “rational explanation” to a point, I can’t imagine a better or more straightforward explanation.
Dabney also mentions a “peculiar view of some Trinitarians” in which the sonship of Christ is given “a merely temporal meaning.” Among these are “the notorious Alex. Campbell.”