The NT witness

From a great post from Glen Scrivener summing up the philosophy behind some of his recent posts on the parables

New Testament does not mean 'gospel'. It doesn’t mean 'gospel' any more than Old Testament means 'gospel'. Rather, both are witnesses to Christ.

You see it’s not the New Testament that fulfils the Old

No. Jesus fulfils the OT, not the NT. There’s a difference. It’s He that stands above both Scriptures.

[...]

The Old is in need of fulfilment in Christ yes. But so is the New. To understand Old or New demands that we read them as witness to Jesus.

It reminds me a little of The Solid Declaration of the Formula of Concord:

the term Gospel is not always employed and understood in one and the same sense, but in two ways, in the Holy Scriptures, as also by ancient and modern church teachers. For sometimes it is employed so that there is understood by it the entire doctrine of Christ, our Lord, which He proclaimed in His ministry upon earth, and commanded to be proclaimed in the New Testament, and hence comprised in it the explanation of the Law and the proclamation of the favor and grace of God, His heavenly Father, as it is written, Mark 1, 1: The beginning of the Gospel of Jesus Christ, the Son of God. And shortly afterwards the chief heads are stated: Repentance and forgiveness of sins [...] So Paul, too, calls his entire doctrine the Gospel, Acts 20, 21; but he embraces the sum of this doctrine under the two heads: Repentance toward God and faith toward our Lord Jesus Christ. [...] Furthermore the term Gospel is employed in another, namely, in its proper sense, by which it comprises not the preaching of repentance, but only the preaching of the grace of God, as follows directly afterwards, Mark 1, 15, where Christ says: Repent, and believe the Gospel. (source)

Although I'm also thankful to Glen for reminding me to make what I think the Gospel is fit Christ, and not Christ fit what I think the Gospel is (see his excellent post "Jesus, not some Christ-principle").