The Orthodox Christian View of Trinity

     The following notes were extracted from SYSTEMATIC THEOLOGY, by L.
Berkhof, Eerdmans: Grand Rapids, 1941 (Fifteenth Printing, 1977).  They
represent a main-stream view of the Trinity.  Statements in square brackets
are my comments, not those of Berkhof.  The balance of the material is a
summary or direct quote (when in quotation marks) from Berkhof.

     In its most summary form, the doctrine is as follows:

     There is in the divine being but one indivisible essence; in this one
divine being there are three persons or individual subsistences, Father,
Son and Holy Spirit; the whole undivided essence of God belongs equally to
each of the three persons; the subsistence and operation of the three
persons in the divine being is marked by a certain definite order; there
are certain personal attributes by which the three persons are
distinguished; and the church confesses the Trinity to be a mystery beyond
the comprehension of man.

     Taking each of these individually:

     A.   There is in the divine being but one indivisible
          essence

     Throughout any discussion of the Trinity the words used and the way
they are used are of critical importance.  Here the word "essence" is of
great importance.  The word comes from the Latin word "esse," meaning "to
be," and has the connotation of energetic being.  The words "being" and
"substance" can be used in a similar way.

     B.   In this one divine being there are three persons or individual
          subsistences, Father, Son and Holy Spirit

     The terms "persons" and "subsistences" are critical here and other
terms have been used as well.  The Schoolmen [i.e. those studying and
writing under the banner of St. Thomas Aquinas] found the word "person"
misleading and the word "substance" vague and coined the word
"subsistence."  Berkhof says: "The variety of the terms used points to the
fact that their inadquacy 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 not 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 [which is
modalism, I believe], as Sabellius taught, but of existence or subsistence.
Thus Calvin says: 'By person, I mean a subsistence in the Divine essence -
a subsistence which, while related to the other two, is distinguished from
them by incommunicable properties.'  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.'"  [Subsistence in this discussion can, I believe, be generally
read to mean "existence in."]

     C.   The whole undivided essence of God belongs equally to each of the
          three persons

     "This means that the divine essence is not divided amoung
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."  Berkhof then
makes a comparison between the divine nature and human nature, noting that
three humans would share in their human nature as members of a species,
where the three persons in the Trinity share in a single divine nature.  In
other words, three humans are three of a kind; the divine persons do
not share a kind or species, but are a unity.  "God" as an essence, does
not have an existence outside the three divine persons.  Berkhof goes on to
say that a corollary to this proposition is that the three persons are not
subordinated to one another in essence, but only as to order and
relationship.

     D.   The subsistence and operation of the three persons in
          the divine being is marked by a certain definite order

     "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."

     E.   There are certain personal attributes by which the
          three persons are distinguished

     "These are also called opera ad intra [roughly translated, 'inside
works'], 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
['outside works'], or those activities and effects by whixh 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."

     F.   The church confesses the Trinity to be a mystery beyond the
          comprehension of man.

     "The many efforts that were made to explain the mystery were
speculative rather than theological.  They invariably resulted in the
development of tritheistic or modalistic conceiptions of God, in the denial
of either the unity of the divine essence or the reality of the personal
distinctions within the essence.  The real difficulty lies in the relation
in which the persons in the Godhead stand to the divine essence and to one
another; and this is a difficulty which the Church cannot remove, but only
try to reduce to its proper proportion by a proper definition of terms."