The following quote is by Christian martyr Michael Sattler. He proclaimed and defended the true Gospel of Jesus Christ. He came against the false gospel of Roman Catholicism. It cost him his life.
“… If the Turks should come, we ought not to resist them; for it is written: Thou shalt not kill. We must not defend ourselves against the Turks and others of our persecutors, but are to beseech God with earnest prayer to repel and resist them. But that I said, that if warring were right, I would rather take the field against the so-called Christians, who persecute, apprehend and kill pious Christians, than against the Turks, was for this reason: The Turk is a true Turk, knows nothing of the Christian faith; and is a Turk after the flesh; but you, who would be Christians, and who make your boast of Christ, persecute the pious witnesses of Christ, and are Turks after the spirit.”
Note that persecution came from both the Roman Catholics and the Protestants.