Awhile back, a person interested in Catholicism/Christianity asked me to explain the Trinity. This subject can be like getting hit with a piercing brain freeze after taking a swig or bite of something ice cold. And not that I claim to be a master at explaining such an abstract topic; rather studying Tertullian, Thomas Aquinas, and the likes of them has helped distill the complexities into how I typically explain it.
In short, I refer to God the Father as “to be,” Jesus as “to know,” and the Holy Spirt as “to act.” In other words, in our human minds, God is not completely knowable; he is outside of space, time, and material being. We come to *know* God through Jesus, who is “consubstantial” with the Father (as said in the Creed) and gives us the path to have a relationship with God, based first on faith and then how we remain morally obedient to the relationship. The Holy Spirit then gives the soul the means to carry out this faith and nurture the relationship with God — while also being consubstantial with the Father and the Son.
And thought the above explanation is quite a bit simplified, it connects with Justin’s and Tertullian’s teachings about the Logos and showing how Jesus is the Logos incarnate and eternal. Keeping in mind that Hellenism influenced many philosophies — and even the various early Christian movements — in the first few centuries AD (Irvin and Sunquist 20, 90), Justin and Tertullian lived right in the thick of all the competing worldviews. For example, Justin, when compared to Tertullian, was more open to incorporating Greek philosophy; he even credited Plato and Socrates for building out what he considered a partial understanding of the Logos (Irvin and Sunquist 120).
Yet, in his Second Apology, Justin doesn’t mince words about what he sees as Logos itself and how we can come to know this. That is, through Jesus Christ. From this central point, and through the relationship between God the Father and Jesus the Son, Justin takes the Greek version of Logos (as a more impersonal, mostly ambiguous concept) and turns it into a more knowable, defined idea. He does this by giving God attributes, that God is the definition of goodness. And we come to know his goodness not by giving God a name (which is a bit arbitrary to Justin), but by explaining that Jesus has always existed as the Logos; and that by becoming man, Jesus fulfilled God’s will to offer salvation through the Logos made flesh (Justin ch. 6).
Tertullian, on the other hand, saw major flaws in the Greek philosophies that surrounded him. Although he ironically did come from the Stoic school of thought (Irvin 141), he saw Greek philosophies as generally vapid and corrupt. So much so that he also saw them as nefarious, linking the various heresies at the time to Greek schools of thought: Valentinus injected Platonism into Gnosticism, Marcion pushed Stoic ideas, and so on. Tertullian saw this mixture of ideas as confounding, perversive, a clear sign of apostacy, and straying far away from “palmary faith” (Tertullian ch. IV, VII).
All that said, it appears that Justin’s and Tertullian’s individual efforts helped push the Catholic church in a more unified direction – even despite Justin taking a best-of-both-worlds approach to Greek philosophy and Christian theology (Irvin and Sunquist 120). Perhaps Tertullian’s harsh view of Greek philosophy helped balance out Justin’s position. Moreover, think about Irenaeus’ Against Heresies and his causing a major turning point in how the church battled heresies and bunk ideas. Collectively, Tertullian and Justin surely had a hand in making that happen.
Works Cited
Irvin, Dale T., and Scott W. Sunquist. History of the World Christian Movement: Earliest Christianity to 1453. Maryknoll: Orbis Books, 2001.
Justin Martyr. Second Apology. Coakley, John W., and Andrea Sterk. Readings in World Christian History, Volume 1: Earliest Christianity to 1453. New York: Orbis Books, 2004.
Tertullian. Second Apology. Translated by Holmes, Rev Peter. http://www.earlychristianwritings.com/text/tertullian11.html