Philip Schaff was one of the leading historians of the nineteenth century and one of the most public theologians and prominent intellectuals of his time. Schaff played a foundational role in the development of American Protestantism and gained wide recognition as one of the leading experts on matters of theology, history, and biblical studies. He was a widely respected scholar and a prolific writer, and his works were influential in both Europe and America.

"He who wishes to grow strong in his religious life, let him, I say, next to the Bible, feed himself on the great Creeds of the Church. There is a force of religious inspiration in them which you will seek in vain elsewhere. And this for good reasons. First, because it is ever true that it is by the truth that sanctification is wrought. And next, because the truth is set forth in these Creeds with a clearness and richness with which it is set forth nowhere else. For these Creeds are not the products of metaphysical speculation, as many who know infinitesimally little about them are prone to assert, but are the compressed and weighted utterances of the Christian heart.

"I do not think I go astray, therefore, when I say to you in all seriousness that the second and third volumes of Dr. Schaff’s Creeds of Christendom have in them more food for your spiritual life — are 'more directly, richly and evangelically devotional' — than any other book, apart from the Bible, in existence."