Martyrological theory of atonement

A big title for a small post.

Revelation 1:4 summarizes Jesus’ work with three phrases: faithful witness, firstborn out of dead, ruler of kings of the earth. That is, He was faithful to death, rose again, and was exalted over all.

Now, in the context, Cur Deus Homo ? Assume John’s notion of “witness” from his gospel, with its background in the Isaianic (and generally prophetic) divine lawsuit. Jesus had to die because that was the limit of faithful witness. He carried the Father’s case to the cross, and because He had served faithfully as the Father’s witness, the Father pronounced a verdict of “righteous” at the resurrection, and made His righteous one Firstborn and Ruler.

If we developed that further, what would a “witness” theology of the atonement look like?