Spiritual Equality, the Black Codes, and the Americanization of the Freedmen
The notion of spiritual equality grew from the abolitionist movement - the precursor for the political ideology of the radical Republicans. The radical Republicans did not think one could achieve the acceptance of spiritual equality through forced material equality. [I]t was a religious revival that brought our country to confront the reality of slavery. It was a theological doctrine from which we derived our notion of equality in the Reconstruction Amendments. And in that era, the free-thinkers - the secularists of the age - were temporizers on the issue. They were simply of no use in the raising to liberty of three and one-half million human beings. If it was religion that brought this country its greatest act of rectification (however incomplete it turned out to be), then we ought not exile it from political forum today through historically inaccurate views of the Constitution.
David F. Forte, Spiritual Equality, the Black Codes, and the Americanization of the Freedmen, 43 Loyola Law Review 569 (1998)