Mr. Henderson on sola Scriptura

The Lutheran pastor Mark Henderson had the following to say in a recent comment at his blog:

M.A. Henderson said...
The new covenant is indeed greater than the old, but that doesn't justify a "let's not read the Old Testament then" mentality - although that has indeed been a popular view in the modern church,a nd it doesn't srprise me that the Mennonites would advocate this, Matthias.

Lutherans have often taught that the OT contains the promises and the NT the fulfilment, which helps to keep the unity of the two testaments in view.

Let's not forget that for the first Christians the OT was their complete Bible, and yet their faith was by no means inadequate; but of course, they had the oral preaching of the Apostles. This is the germ of truth in the RC theory of oral tradition which they have since distorted - they hold that some aspects of tradition, e.g. the Marian dogmas, are Apostolic despite the fact that scripture knows nothing of them, we hold that everything necessary for salvation and for the faith and life of the church has been set down by the Apostles in the NT.
Tuesday, 04 May, 2010
[http://acroamaticus.blogspot.com/2010/05/aquinas-on-primacy-of-scripture-ii.html]

I quote the whole comment because, unlike some bloggers, I abhor the very thought of taking someone out of context, but it's the last part in which I'm interested here:

we hold that everything necessary for salvation and for the faith and life of the church has been set down by the Apostles in the NT

So we have the proposition:

everything necessary for salvation and for the faith and life of the church has been set down by the Apostles in the NT

Evidently that proposition would itself be "necessary for salvation and for the faith and life of the church". So ... whereabouts is that "set down by the Apostles in the NT"? Mr. Henderson? Anyone?

Reginaldvs Cantvar
Feast of St. Peter Celestine, Pope, Confessor, and of St. Pudentiana, Virgin, A.D. 2010