Here on the Encyclopedia Britannica Blog. This passage accurately captures what the disagreement -- not just between them, but between those wishing to see in America's Founding, "secularism" on the one hand, or "religion" on the other -- is all about:
The core of our disagreement, as I see it, is the definition of religion. If the definition is quite broad, the belief that there are providential forces at work in the world which mere humans can never fully understand, or the belief that there are certain rights (i.e., life, liberty, and the pursuit of happiness) that should be granted a semi-sacred status in America’s “civil religion,” then all the prominent Founders were religious.
If the definition is more narrowly Christian, to include the belief that Jesus was the divine son of God, and the belief there is life after death in a heavenly location where the saints communed everlastingly with God, then the matter gets much messier. Different Founders took somewhat different postures on these issues, and several of them changed their positions during their respective lifetimes.