It is to be numbered among the evils of our day, that the churches are so divided one from another, that there is scarcely any friendly intercourse strengthened between us; much less does that holy communion of the members of Christ flourish, which all profess with the mouth, but few sincerely regard in the heart.
But if the principal teachers conduct themselves more coldly than they ought, it is principally the fault of the princes who, involved in their secular concerns, neglect the prosperity and purity of the church; or each one, contented with his own security, is indifferent to the welfare of others.
Thus it comes to pass, that the members being divided, the body of the church lies disabled. Respecting myself, if it should appear that I could render any service, I should with pleasure cross ten seas, if necessary, to accomplish that object.
From John Calvin’s Letter to Archbishop Cranmer (1552)