[Recapitulation: On the Trinity]
a. There is in the Divine Being but one indivisible essence (ousia, essentia). God is one in His essential being or constitutional nature. Some of the early Church Fathers used the term “substantia” as synonymous with “essentia,” but later writers avoided this use of it in view of the fact that in the Latin Church “substantia” was used as a rendering of “hupostasis” as well as of “ousia,” and was therefore ambiguous. At present the two terms “substance” and “essence” are often used interchangeably. There is no objection to this, provided we bear in mind that they have slightly different connotations. Shedd distinguishes them as follows: “Essence is from esse, to be, and denotes energetic being (Augustine On the Trinity 5.2). Substance is from substare, and denotes the latent possibility of being.… The term essence describes God as a sum-total of infinite perfections; the term substance describes Him as the underlying ground of infinite activities. The first is, comparatively, an active word; the last, a passive. The first is, comparatively, a spiritual, the last a material term. We speak of material substance rather than of material essence.” /1/ Since the unity of God was already discussed in the preceding, it is not necessary to dwell on it in detail in the present connection. This proposition respecting the unity of God is based on such passages as Deut. 6:4; Jas. 2:19, on the self-existence and immutability of God, and on the fact that He is identified with His perfections as when He is called life, light, truth, righteousness, and so on.
b. In this one Divine Being there are three Persons or individual subsistences, Father, Son, and Holy Spirit. This is proved by the various passages referred to as substantiating the doctrine of the Trinity. To denote these distinctions in the Godhead, Greek writers generally employed the term hupostasis, while Latin authors used the term persona, and sometimes substantia. Because the former was apt to be misleading and the latter was ambiguous, the Schoolmen coined the word subsistentia. The variety of the terms used points to the fact that their inadequacy was always felt. It is generally admitted that the word “person” is but an imperfect expression of the idea. In common parlance it denotes a separate rational and moral individual, possessed of self-consciousness, and conscious of his identity amid all changes. Experience teaches that where you have a person, you also have a distinct individual essence. Every person is a distinct and separate individual, in whom human nature is individualized. But in God there are no three individuals alongside of, and separate from, one another, but only personal self-distinctions within the Divine essence, which is not only generically, but also numerically, one. Consequently many preferred to speak of three hypostases in God, three different modes, not of manifestation, as Sabellius taught, but of existence or subsistence. Thus Calvin says: “By person, then, I mean a subsistence in the Divine essence.—a subsistence which, while related to the other two, is distinguished from them by incommunicable properties.”/2/ This is perfectly permissible and may ward off misunderstanding, but should not cause us to lose sight of the fact that the self-distinctions in the Divine Being imply an “I” and “Thou” and “He,” in the Being of God, which assume personal relations to one another. Matt. 3:16; 4:1; John 1:18; 3:16; 5:20–22; 14:26; 15:26; 16:13–15.
c. The whole undivided essence of God belongs equally to each of the three persons. This means that the divine essence is not divided among the three persons, but is wholly with all its perfection in each one of the persons, so that they have a numerical unity of essence. The divine nature is distinguished from the human nature in that it can subsist wholly and indivisibly in more than one person. While three persons among men have only a specific unity of nature or essence, that is, share in the same kind of nature or essence, the persons in the Godhead have a numerical unity of essence, that is, possess the identical essence. Human nature or essence may be regarded as a species, of which each man has an individual part, so that there is a specific (from species) unity; but the divine nature is indivisible and therefore identical in the persons of the Godhead. It is numerically one and the same, and therefore the unity of the essence in the persons is a numerical unity. From this it follows that the divine essence is not an independent existence alongside of the three persons. It has no existence outside of and apart from the three persons. If it did, there would be no true unity, but a division that would lead into tetratheism. The personal distinction is one within the divine essence. This has, as it is usually termed, three modes of subsistence. Another conclusion which follows from the preceding, is that there can be no subordination as to essential being of the one person of the Godhead to the other, and therefore no difference in personal dignity. This must be maintained over against the subordinationism of Origen and other early Church Fathers, and the Arminians, and of Clarke and other Anglican theologians. The only subordination of which we can speak, is a subordination in respect to order and relationship. It is especially when we reflect on the relation of the three persons to the divine essence that all analogies fail us and we become deeply conscious of the fact that the Trinity is a mystery far beyond our comprehension. It is the incomprehensible glory of the Godhead. Just as human nature is too rich and too full to be embodied in a single individual, and comes to its adequate expression only in humanity as a whole so the divine Being unfolds itself in its fulness only in its three fold subsistence of Father, Son, and Holy Spirit.
d. The subsistence and operation of the three persons in the divine Being is marked by a certain definite order. There is a certain order in the ontological Trinity. In personal subsistence the Father is first, the Son second, and the Holy Spirit third. It need hardly be said that this order does not pertain to any priority of time or of essential dignity, but only to the logical order of derivation. The Father is neither begotten by, nor proceeds from any other person; the Son is eternally begotten of the Father, and the Spirit proceeds from the Father and the Son from all eternity. Generation and procession take place within the Divine Being, and imply a certain subordination as to the manner of personal subsistence, but no subordination as far as the possession of the divine essence is concerned. This ontological Trinity and its inherent order is the metaphysical basis of the economical Trinity. It is but natural, therefore, that the order existing in the essential Trinity should be reflected in the opera ad extra that are more particularly ascribed to each one of the persons. Scripture clearly indicates this order in the so-called praepositiones distinctionales, ek, dia, and en, [distinctions between the prepositions, “our of”, “through” and “in”] which are used in expressing the idea that all things are out of the Father, through the Son, and in the Holy Spirit.
e. There are certain personal attributes by which the three persons are distinguished. These are also called opera ad intra, because they are works within the Divine Being, which do not terminate on the creature. They are personal operations, which are not performed by the three persons jointly and which are incommunicable. Generation is an act of the Father only; filiation belongs to the Son exclusively; and procession can only be ascribed to the Holy Spirit. As opera ad intra these works are distinguished from the opera ad extra, or those activities and effects by which the Trinity is manifested outwardly. These are never works of one person exclusively, but always works of the Divine Being as a whole. At the same time it is true that in the economical order of God’s works some of the opera ad extra are ascribed more particularly to one person, and some more especially to another. Though they are all works of the three persons jointly, creation is ascribed primarily to the Father, redemption to the Son, and sanctification to the Holy Spirit. This order in the divine operations points back to the essential order in God and forms the basis for what is generally known as the economic Trinity.
THE ETERNAL GENERATION OF THE SON
c. The eternal generation of the Son. The personal property of the Son is that He is eternally begotten of the Father (briefly called “filiation”), and shares with the Father in the spiration of the Spirit. The doctrine of the generation of the Son is suggested by the Biblical representation of the first and second persons of the Trinity as standing in the relation of Father and Son to each other. Not only do the names “Father” and “Son” suggest the generation of the latter by the former, but the Son is also repeatedly called “the only-begotten,” John 1:14, 18; 3:16, 18; Heb. 11:17; 1 John 4:9. Several particulars deserve emphasis in connection with the generation of the Son: (1) It is a necessary act of God. Origen, one of the very first to speak of the generation of the Son, regarded it as an act dependent on the Father’s will and therefore free. Others at various times expressed the same opinion. But it was clearly seen by Athanasius and others that a generation dependent on the optional will of the Father would make the existence of the Son contingent and thus rob Him of His deity. Then the Son would not be equal to and homoousios [of the same essence] with the Father, for the Father exists necessarily, and cannot be conceived of as non-existent. The generation of the Son must be regarded as a necessary and perfectly natural act of God. This does not mean that it is not related to the Father’s will in any sense of the word. It is an act of the Father’s necessary will, which merely means that His concomitant will takes perfect delight in it. (2) It is an eternal act of the Father. This naturally follows from the preceding. If the generation of the Son is a necessary act of the Father, so that it is impossible to conceive of Him as not generating, it naturally shares in the eternity of the Father. This does not mean, however, that it is an act that was completed in the far distant past, but rather that it is a timeless act, the act of an eternal present, an act always continuing and yet ever completed. Its eternity follows not only from the eternity of God, but also from the divine immutability and from the true deity of the Son. In addition to this it can be inferred from all those passages of Scripture which teach either the pre-existence of the Son or His equality with the Father, Mic. 5:2; John 1:14, 18; 3:16; 5:17, 18, 30, 36; Acts 13:33; John 17:5; Col. 1:16; Heb. 1:3. The statement of Ps. 2:7, “Thou art my Son; this day have I begotten thee,” is generally quoted to prove the generation of the Son, but, according to some, with rather doubtful propriety, cf. Acts 13:33; Heb. 1:5. They surmise that these words refer to the raising up of Jesus as Messianic King, and to the recognition of Him as Son of God in an official sense, and should probably be linked up with the promise found in 2 Sam. 7:14, just as they are in Heb. 1:5. (3) It is a generation of the personal subsistence rather than of the divine essence of the Son. Some have spoken as if the Father generated the essence of the Son, but this is equivalent to saying that He generated His own essence, for the essence of both the Father and the Son is exactly the same. It is better to say that the Father generates the personal subsistence of the Son, but thereby also communicates to Him the divine essence in its entirety. But in doing this we should guard against the idea that the Father first generated a second person, and then communicated the divine essence to this person, for that would lead to the conclusion that the Son was not generated out of the divine essence, but created out of nothing. In the work of generation there was a communication of essence; it was one indivisible act. And in virtue of this communication the Son also has life in Himself. This is in agreement with the statement of Jesus, “For as the Father hath life in Himself, even so gave He to the Son also to have life in Himself,” John 5:26. (4) It is a generation that must be conceived of as spiritual and divine. In opposition to the Arians, who insisted that the generation of the Son necessarily implied separation or division in the divine Being, the Church Fathers stressed the fact that this generation must not be conceived in a physical and creaturely way, but should be regarded as spiritual and divine, excluding all idea of division or change. It brings distinctio and distributio, but no diversitas and divisio in the divine Being. (Bavinck) The most striking analogy of it is found in man’s thinking and speaking, and the Bible itself seems to point to this, when it speaks of the Son as the Logos. (5) The following definition may be given of the generation of the Son: It is that eternal and necessary act of the first person in the Trinity, whereby He, within the divine Being, is the ground of a second personal subsistence like His own, and puts this second person in possession of the whole divine essence, without any division, alienation, or change.
/1/ Dogm. Theol., I, p. 271. Quoting from the new edition – Essence is derived from esse (to be) and denotes energetic being. (Augustine, On the Trinity 5.2). Substance is from substare and denotes the latent potentiality of being…The term essence describes God as a sum total of infinite perfections; the term substance describes him as the underlying ground of infinite activities. The first is, comparatively, an active word; the last, a passive. The first is comparatively a spiritual; the last, a material term. We speak of a material substance rather than of a material essence. W.G.T. Shedd, Dogmatic theology. 3rd ed.A. W. Gomes, ed. (P & R, 2003), p. 232.
/2/ John Calvin, Inst. I, XIII, 6
Louis Berkhof, Systematic Theology (Eerdmans, 1938), pp. 87-89, 92-94.