Harnack on the Old Testament

To keep it [the Old Testament] after the nineteenth century as a canonical document within Protestantism results from a religious and ecclesiastical paralysis.

Quoted here.

Here's a direct response from Wilhelm Vischer:

By this step we abandon the Christian confession - the confession that Jesus of Nazareth is the Christ. ... For Christianity means precisely the confession that Jesus is Christ in the sense in which the Old Testament defines Israel's messiah. The New Testament understands it in this way. ... With complete consistency the early church took over Israel's scripture.

Somewhat related, Hadassah links to an article on theology and anti-semitism. It talks of an apparent "Abraham complex," in which theological anti-semitism has its root in "the conflict between Christianity or Islam as the true religion and Judaism as the religion that started it all."