Timothy George argues that Lincoln was “the most spiritually minded president in American history”:
So why did he never join a church himself? Two reasons. First, he was offended by the religious rivalry and braggadocio of the frontier preachers of his day. None of them made a compelling case to his lawyerly mind that only one denomination was right and all the others wrong. Further, Lincoln was reticent, “the most shut-mouthed man I know,” as his law partner William Herndon said. He did not want to cross the thin line between sincerity and self-righteousness. There was nothing smug about Lincoln’s faith.
Lincoln’s great achievement was to see the terrible times through which he lived in the context of God’s providential purposes. He referred to America as the almost-chosen nation and came to see himself as a “chosen instrument in the hands of the Almighty.” His firm belief that God is concerned for history and reveals his will in it drew on the wisdom of the Hebrew prophets, the teachings of the New Testament refracted through the tradition of St. Augustine, and the Calvinistic Baptists among whom he grew up. Though he read Voltaire as a young man, he had no interest in a deist God who dumbly peers down on human struggles. The God of Lincoln meets us in judgment and mercy and in the crucible of suffering that shapes the destiny of us all.