Blog 26: 1.13.26 - 1.13.29
In these final sections of chapter 13 Calvin considers two arguments against the Trinity. Theologically, the anti-Trinitarians argued that Christ's subordination to the Father was counterevidence to the Trinity (section 26). Historically, they appealed to the Church Fathers against the Trinity (section 27-28).
The anti-Trinitarians argue that the Father is greater than the Son (cf. John 14:28), that the Son is thereby inferior to the Father and hence not of the same divine essence. But Calvin shows that the Father and Son have a difference of "order" but are of the same "essence." Their roles are distinct but ontologically they share the same nature.
The anti-Trinitarians appeal for support to Irenaeus, who in Against Heresies often says that the Father of Christ is the sole and eternal God of Israel. But Calvin shows that Irenaeus (1) used this language because he was refuting those who denied that the Father of Christ was the same person throughout the Bible, and (2) elsewhere explicitly argued for Christ's eternal divinity and oneness with the Father.
Calvin admits that Tertullian's wording was at times more problematic ("sometimes rough and thorny in his mode of speech"). But Calvin shows that his meaning and intention is still fully Trinitarian.
Then, in the final section, Calvin briefly demonstrates the same regarding Justin Martyr, Hilary of Poitiers, Ignatius of Antioch, and Augustine ("toward whom these rascals are most hostile").
Calvin has shown that the Trinity is biblical, can withstand objections, and has the full support of the Early Church. In his concluding paragraph Calvin issues a reminder that all of us should heed in our theological explorations: we should seek faithful exposition and edification but put a limit on our curiosity and not delight in speculation that would profit us little (cf. Deut. 29:29).