@slimboyfat
First of all, I note that even the Arian creeds acknowledged about the Son:
- "He who has begotten the only-begotten Son before aeonian times (χρόνων αἰωνίων), through whom also he made the aeons and everything..." (Profession of Faith of Arius)
- "And if anybody teaches contrary to the sound, right faith of the Scriptures, alleging that either time or occasion or age exists or did exist before the Son was begotten, let him be anathema." (Dedication Creed)
- "who before all ages and before all beginning and before all conceivable time and before all comprehensible substance (οὐσίας) was begotten impassibly from God through whom the ages were set up and all things came into existence" (Homoiousian Creed of Nike)
Here is a more balanced treatise on Tertullian:
A recurring claim among antitrinitarians and certain critics of Nicene orthodoxy is that some early Christian writers, such as Tertullian, supposedly denied the eternal generation of the Son—asserting instead that God “became” Father only once the Son came into existence. The quote most often cited in this regard is from Against Hermogenes, chapter 3, where Tertullian writes:
“There was, however, a time when neither sin existed with Him, nor the Son; the former of which was to constitute the Lord a Judge, and the latter a Father.”
On a superficial reading, it might appear that Tertullian is affirming that the Son had a beginning in time. But this is not a sound or complete interpretation of either the passage or Tertullian's larger theology. Let’s unpack why this argument collapses under scrutiny. Tertullian is engaging with Hermogenes’ dualistic teaching that matter existed eternally alongside God, and that God has always been “Lord” over it. Tertullian’s response is that terms like “Lord,” “Father,” and “Judge” are relational titles, and do not refer to God's essence (substantia) but to His relation to creation and sin:
“God is the designation of the substance itself… but ‘Lord’ is not a designation of substance, but of power.” (Adv. Hermog. 3)
In other words, God has always been God by nature, but titles like “Father” or “Judge” arise only with the existence of a Son or of sin—from our perspective in time and history. These are not ontological changes in God, but logical or economic designations. As Aquinas later explains:
“In God, generation is eternal, not temporal, since God is outside of time.” (ST I, q.27, a.2)
Tertullian’s rhetorical device—“there was a time when… the Son was not”—should not be read as a denial of the eternal Logos but as an explanation of why titles like 'Father' or 'Lord' appear progressively in Scripture (e.g., Genesis 2:15 introduces “Lord God”). In Adversus Praxean, his key anti-modalist work, Tertullian clearly teaches the Son’s eternal preexistence, as the divine Logos within the Father:
“Even before all things, God was not alone, for He had within Himself Reason [Logos], and Reason was in Him as His own substance.” (Adv. Prax. 5)
This “Word,” he writes, proceeds from the Father—not as a creation, but as an emanation from the divine substance:
“Whatever therefore was the substance of the Word… I claim for it the name of Son; and while I recognize the Son, I assert His distinction as second to the Father.” (Adv. Prax. 7)
This aligns perfectly with the later Nicene formulation: the Son is begotten, not made, consubstantial (ὁμοούσιος) with the Father.
Antitrinitarians often quote Tertullian’s phrase:
“The Father is the whole substance, but the Son is a derivation and portion of the whole.” (Adv. Prax. 9.2)
But this language reflects eternal generation, not subordination or creaturehood. Tertullian uses the term portio in a Stoic context—not to imply division of essence, but participation without separation. As he clarifies:
“The Father and the Son are of one substance, but the persons are distinct.” (Adv. Prax. 13)
This is fully Trinitarian in substance, if not yet in post-Nicene vocabulary. The Son derives from the Father as Light from Light—“not made,” but eternally begotten. According to Thomas Aquinas, God’s paternity is not accidental or acquired in time. Rather, the Father is eternally Father because the Son is eternally begotten:
“The divine persons are distinguished by relations alone, and paternity is a real relation founded on the eternal generation of the Son.” (ST I, q.28, a.1)
If God were not eternally Father, then something would be added to His nature when He becomes Father—contradicting divine immutability (cf. ST I, q.9), which Scripture itself affirms:
- “I the Lord do not change.” (Malachi 3:6)
- “With God there is no variation or shadow due to change.” (James 1:17)
Thus, the Father must always be Father, because the Son is eternally from Him. Despite his occasional use of imprecise language (understandable before the Nicene debates), Tertullian explicitly affirms the Son’s full divinity and personal distinction from the Father and the Spirit:
- He is the Word eternally in God (Adv. Prax. 5).
- He is God and yet distinct from the Father (Adv. Prax. 13).
- He is Creator of all things, not a creature (Adv. Prax. 7).
- He is not an angel, but divine in nature (De Carne Christi 14).
His famous formula—“una substantia, tres personae”—prefigures the Nicene and later Trinitarian orthodoxy. Far from Arianism, Tertullian is a Trinitarian pioneer, combating both modalism and subordinationism. So your argument that “Tertullian said there was a time when the Son was not” collapses once:
- Context is properly understood.
- His full writings are considered.
- The philosophical and theological vocabulary of his time is taken into account.
He affirmed that the Son, as Word and Wisdom, existed eternally in God, proceeding from the Father but not as a created being. He anticipated Nicene theology by affirming the unity of substance and the real distinction of persons. Therefore, Tertullian cannot be invoked as a witness against the Trinity, unless one quotes him selectively and ignores his overall theological vision. As the Catechism of the Catholic Church affirms:
“The Church’s faith confesses that the Word who became flesh is the Son of the eternal Father. He was not made, but begotten, not in time but from eternity.” (CCC 262)
So did Tertullian.