The Mystery of the Trinity Part 4

Part 4: Relations of Origin and the Distinction of Persons

If God is one in essence and simple in being, then how can we say that there are three distinct persons in God? We have already seen that these distinctions arise from two eternal processions: the Son is begotten by the Father through divine knowledge, and the Spirit proceeds from the Father and the Son through divine love.

But what exactly makes the Father the Father, and not the Son? What makes the Holy Spirit a distinct person? In this part, we explore how the divine persons are distinguished not by substance, but by relations of origin—real, eternal, and personal.

Relations of Origin in God

In God, there are no material parts and no accidents. So how can there be distinction at all? The answer lies in relation.

According to St. Thomas Aquinas and the Church’s tradition, the divine persons are really distinct from one another by opposed relations of origin. That is, each person is identified by how they relate to the others as origin or as one who proceeds.

Let us recall the two eternal processions:

• The Son is begotten by the Father through divine self-knowledge.

• The Holy Spirit proceeds from the Father and the Son through divine love.

These processions give rise to four real relations:

1. Paternity – the Father’s relation to the Son

2. Filiation – the Son’s relation to the Father

3. Active spiration – the shared act of the Father and Son toward the Spirit

4. Passive spiration – the Spirit’s origin from the Father and the Son

   
   

Three Persons, Not Four

If there are four relations, why are there only three persons?

The answer lies in opposition. A relation only constitutes a distinct person if it is opposed to another. Paternity is opposed to filiation—thus, Father and Son are distinct. Passive spiration is opposed to active spiration—thus, the Spirit is distinct from the other two.

But active spiration is not opposed to either paternity or filiation. It is a shared relation, not one that constitutes a new person. Therefore, from four relations, only three mutually opposed pairs emerge, and so three persons.

Each divine person is a subsisting relation in the divine essence.

To say that a person is subsisting means that the person exists in itself, not as a property or part of something else. A subsisting person is not something God merely has; it is someone who is. In created terms, a human being is a subsisting subject with a human nature. In the Trinity, each divine person is a real, personal subject who possesses the full divine nature—not as a fragment, but as the whole.

• The Father is unbegotten and begets the Son.

• The Son is begotten by the Father.

• The Holy Spirit proceeds from the Father and the Son.

These relations are real, personal distinctions, but they do not divide the divine substance. The divine essence is one, and each person possesses it fully.

Relation in God Is Not Accidental

In created things, relations are usually accidental. A man may become a father when his child is born, but that relation does not change what he is. It comes and goes without altering his substance.

In God, this is not the case. God is pure act, and His relations are not added on. They are identical with His being. The relation of paternity is not something the Father has in addition to His essence. It is the Father’s very way of existing in the divine essence. Likewise, filiation and spiration are not properties but personal modes of subsisting in the one, undivided nature of God.

This means that relation in God is substantial, not accidental. The persons are real, not symbolic or functional. And because relation does not divide essence, God remains absolutely one in being.

Why This Matters

This doctrine shows that Trinitarian faith is neither contradictory nor vague. It preserves both the unity of God and the distinction of persons.

• The persons are not phases or appearances.

• They are not inferior or subordinate.

• They are not parts of God or separate centers of action.

Rather, each person is a real, eternal subject, distinguished by how He proceeds from another, not by what He is. Each person is God, and each person is not the other.

This understanding also prepares us to appreciate how the Trinity is revealed in time. The eternal processions give rise to missions, in which the Son and the Spirit are sent into the world—not to begin existing, but to make known who God has always been.

Looking Ahead

In the next part, we will explore these divine missions. The Incarnation of the Son and the outpouring of the Holy Spirit are not temporary roles or new realities. They are temporal expressions of eternal truths. In understanding the missions, we learn how God reveals the Trinity in salvation history.

And in the final post of the series, we will review Trinitarian heresies, both ancient and modern, to help clarify and defend the Church’s consistent and beautiful confession: one God in three persons.

“In the Trinity, nothing is before or after, nothing greater or less. The whole three persons are co-eternal and co-equal.”—Athanasian Creed