Why? According to Calvin, “because I do not embrace their gross and fictitious notion concerning a carnal way of eating Christ in the sacrament.” Thus, not baptism but the mass — was the great watershed between Romanism and Protestantism.
It is very significant that the Protestant Reformer Calvin here repudiates both the Romish doctrine of transubstantiation and the Anabaptist doctrine of antipaidobaptistic revolutionism. For Calvin
never repudiated infant baptism in general, nor the validity of baptisms administered by Rome in particular.
Instead, Calvin here calls the Romanists “internal enemies of the Church.” This shows Calvin considered both himself and the Romanists to be inside the Visible Church of Christ. All of her members — be they Catholics or Protestants — needed ongoing reformation.