Religion, morality, and knowledge being necessary to good government and the happiness of mankind, schools and the means of education shall forever be encouraged.So, here we have two official documents that could be used to support either side of the argument. The truth is, both ideals can be traced to the founding and no amount of cherry-picking can change that. That is Knippenberg's conclusion, too, as he finds that there is plenty of historical evidence two support both a secular and Christian founding of America. As he summarizes:
In sum, while it may well strain credulity to claim that at least some leading members of the founding generation were orthodox religious believers, it is equally incredible to regard them as rigidly bent on an absolute and inflexible separation of church and state, a wall high and impermeable. Whatever their private beliefs, many at least acquiesced in and even encouraged public expression of religion. They respected, admired, and worked with men like Samuel Adams (to be accurate, the beer label should say “Brewer, Patriot, Orthodox Calvinist”). They loved women whose religious orthodoxy they respected and did not discourage.
To my friends on the Christian Right, I say: You don’t have to stretch claims about the Founders to provide historical support for a religion-friendly public square. If your intention is to defend the rights of believers to worship and witness as they please, and to level the proverbial “playing field” as they seek to influence public policy, the founding generation would offer you plenty of aid and comfort. Your reform efforts fall squarely in an American tradition that includes abolitionism, the civil rights movement, the social Gospel, and the temperance movement.
To my friends on the secular Left, I say: a good portion of the moral energy that sustains our democratic republic has its roots in religious faith. The Founders recognized that and were able to accommodate and work with it. Remember the words of George Washington:[L]et us with caution indulge the supposition, that morality can be maintained without religion. Whatever may be conceded to the influence of refined education on minds of a peculiar structure, reason and experience both forbid us to expect that National morality can prevail in exclusion of religious principle.