Trinity and Biblical inerrancy

By popular demand, another Broughtonism:

The doctrine of the Trinity is the glory of the Christian faith. It is drawn entirely from revelation. It depends on the absolute truth of the sentences through which the Scriptures teach us about God and his nature, his character, his purposes, his actions and promises. The doctrine depends, for example, on the infallibility and inerrancy of the teaching in St John's Gospel, or the Epistle to the Ephesians or the last paragraph of St Matthew's Gospel, because the doctrine of the Trinity is not enunciated fully in any one passage but is gathered from many statements of the Scriptures. If we cannot rely on the verbal inspiration of Scripture, the doctrine of the Trinity has no basis.

-"The Implications of the Doctrine of the Trinity for Theology and for Ordinary Life", Appendix B, The Everlasting God (Selected Works, Vol I) p. 153

Broughton insists here on both the infallibility and the inerrancy of Scripture, neither confounding their meanings nor dividing their substance.

God's word spoken and God's word written

Is there a difference between God's word spoken and God's word written?

Well, yes. One is spoken and one is written.

But apart from this, what is the point of making such a distinction? I would have thought that it is both technical and nugatory, given that the only sure access we have to God's word spoken is God's word written.

And I am deeply suspicious of why you would not only want to notice such a distinction, but in any sense talk it up as worth paying attention to.