If there is one thing I've learned about Barth it is this: Read the excursuses in the Church Dogmatics. There are so many treasures to be found in that fine print. Sometimes he makes a passive aggressive comment against another theologian, sometimes he makes a statement that is hysterical, and other times he makes historical observations that are priceless.
Today is no exception . . .
Regarding the Reformed "pedagogic usefulness" of their formulation of the doctrine of election:
"Very different judgments can be passed on the value and usefulness of the doctrine, as history has in fact demonstrated. Where Calvin and his followers saw nothing but suavissimum fructum (sweetest fruit), the Lutherans of the 16th and 17th centuries, and many others too, saw only an endangering of assurance of salvation, the sense of responsibility, etc., or even an open relapse into Stoicism, Manicheism, Quietism, and Libertinism. Boettner appears to rejoice at the supposed kinship between the doctrine of predestination, as understood Calvinistically, and the teaching of Islam. But this supposed kinship was the very reason why the older Lutherans sought to discredit the Calvinists by describing them as secret adherents of the Eastern Antichrist." (II.2, p. 37)