Did you know that the Princeton Seminary faculty, under the leadership of J. Gresham Machen, invited Billy Sunday to preach at the seminary on March 18, 1915? Machen said of Sunday that "His methods are as different as could possibly be imagined from ours, but we support him to a man simply because, in an age of general defection, he is preaching the gospel." (from Calhoun's Princeton Seminary: The Majestic Testimony, p. 299)
This should not be surprising, since Machen said in his book Christianity and Liberalism, "Another difference of opinion is that between the Calvinistic or Reformed Theology and the Arminianism which appears in the Methodist church. ... A Calvinist is constrained to regard the Arminian theology as a serious impoverishment of the Scripture doctrine of divine grace; and equally serious is the view which the Arminian must hold as to the doctrine of the Reformed Churches. Yet here again, true evangelical fellowship is possible between those who hold, with regard to some exceedingly important matters, sharply opposing views."