I am comfortable with the fact that little—probably nothing—of what I write while I am on the earth will be read after I am gone. And though I am sometimes accused of over-confidence, let me be clear: I am at least a little surprised when what I’ve written is read, and when someone says they’ve found it helpful, I only hope they are correct. John Calvin wrote the dedication to his commentary on the gospel of John in the year 1553, when he was in his mid-forties. How about that? How can we do better than to be faithful (but critical) students of such a teacher, as we seek the unity of the faith and of the knowledge of the Son of God?

Calvin begins by demonstrating how the full deity of the Son, the Son’s equality with the Father, and the Son’s identity as distinct from the Father, and thus all essentials of Trinitarian theology, are nailed down in the first verse alone. Put in context, as Calvin explains in the dedication, the emphasis on the deity of the Son defines the gospel as a strictly and gloriously divine dispensation of hope and life imperishable.

In the midst of all that, he makes this comment:

This passage serves, therefore, to refute the error of Sabellius; for it shows that the Son is distinct from the Father. I have already remarked that we ought to be sober in thinking, and modest in speaking, about such high mysteries. And yet the ancient writers of the Church were excusable, when, finding that they could not in any other way maintain sound and pure doctrine in opposition to the perplexed and ambiguous phraseology of the heretics, they were compelled to invent some words, which after all had no other meaning than what is taught in the Scriptures. They said that there are three Hypostases, or Subsistences, or Persons, in the one and simple essence of God.

Sabellianism is also known as modalism, the anti-Trinitarian belief that God is one person only, not three, who works or appears in different modes (Father, Son, Spirit) at different times. If someone believes this, we have reason to worry about their salvation. The Athanasian Creed begins:

Whosoever will be saved, before all things it is necessary that he hold the catholic [universal, true] faith;

Which faith except every one do keep whole and undefiled, without doubt he shall perish everlastingly.

And the catholic faith is this: That we worship one God in Trinity, and Trinity in Unity.

In the quotation above, Calvin explains the use of extra-biblical terminology in theology. That is, sometimes in theology we use words which are not in the Bible. This is true in Trinitarian theology most conspicuously. The word “Trinity,” for example, is not in the Bible. He makes a few helpful points, which I’ll just re-state:

Good theology is often formed in response to error. This has lots of implications for the church. Theological trouble ought to be taken seriously; but theological trouble may be seen as helpful correction, and encouragement and opportunity to seek the Lord while he may be found, to grow in knowledge of the truth. Paul writes, “there must be factions among you in order that those who are genuine among you may be recognized” (1 Cor 11:19), and he says that the church is a “pillar and buttress of the truth” (1 Tim 3:15).

Good theology expresses no other meaning than the teaching of Scripture. Scripture is a deposit of truth beyond value. But Christians are not meant merely to repeat the words of the Bible. The Bible may be translated, explained, and preached. The ‘truth of Scripture’, the truth of the Christian faith, saving truth, includes not only the words in the Bible but the vast riches of the meaning of its words.

All this is especially valuable in the age of the global church. The meaning of the Bible, the Christian faith, the very gospel of life, of the saving work of the Christ Jesus of Nazareth, may be expressed in all the languages of the world. Christian truth was for centuries expressed in Greek, Latin, German, French, Dutch, and English, and others. These days, who knows? There are something like 7,000 spoken languages today. But these things remain the same: the saving truth of the Bible is the stuff of good theology and Christian ministry. The gospel may be expressed in many languages to many people, because there is truth and unity to it all: “one Lord, one faith, one baptism, one God and Father of all, who is over all and through all and in all” (Eph 4:5-6).

Calvin’s commentary on John is available online here and here.