Melanchthon showed Calvin an anti-Zwingli anti-Oecolampadius pamphlet written by a schismatic and Calvin remarked
What good purpose could it serve to assault the Zwinglians every third line, and to attack Zwingli himself in such an unmannerly style? And not even to spare Oecolampadius, that holy servant of God, whom I wish that he resembled, even in being half as good, in which case he would certainly stand far higher in my esteem than he does. O God of grace, what pleasant sport and pastime do we afford to the Papists, as if we had hired ourselves to do their work!”
The last line means that Calvin saw these schismatics as doing more harm to the Reformation than the Papists could ever hope.