The Jefferson Bible
The Life and Morals of Jesus of Nazareth
During the latter years of Thomas Jefferson's life, he took a sharp razor and painstakingly cut out all of the divine and most of the supernatural references to Jesus from the New Testament and pasted them in the corresponding time-line to textual events. He entitled this effort: "The Life and Morals of Jesus of Nazareth." His purpose was to discover the actual teachings without regard to any religious interpretation of those teachings. The result was that the words attributed to Jesus were just as morally sound without being divinely motivated. (Now what Jefferson might have reasoned about Luke 12:47-48 is quite the ethical dilemma, but that verse, in general, is a discussion for a later time.)
An Age of Reason
Thomas Jefferson and his contemporaries were children of the Enlightenment, the natural progression first seeded in the Renaissance where humanity was just beginning to catch the trace glimmers of a world beyond the veil of prevalent theosophy. The process took over 300 years, but was a steady, inevitable growth. With the Age of Reason came a deeper questioning and subsequent yearning for the progress that was possible without doctrinal restraints. Looking to natural law, Jefferson believed that man could self-regulate without dependency on an outside agency...whether that separate agency be through interpretation of God's will by ecclesiastical powers or by the Divine Right of Kings. This did not negate one's choice of faith, but rather it worked together...science and faith as part of the same mechanism.
The Spirit of Inquiry
While the concept of Deism (the natural world as self-evident of higher design, but not dependent on human interpretation of that designer) was growing among intellectuals of the era, Jefferson, himself, made no proclamation of being a Deist, although his central ideas and personal observations aligned and he is reasonably associated with that view. In correspondence to his nephew, Peter Carr, in 1787 he advised: "Question with boldness even the existence of a god; because, if there be one, he must more approve the homage of reason, than that of blindfolded fear." 
God, endowing man with reason, a self-evident trait, would, in a Naturalist's view, be expected to be used.
In his own words (Query XVII of Notes on the State of Virginia): "But it does me no injury for my neighbour to say there are twenty gods, or no god. It neither picks my pocket nor breaks my leg. ... Reason and free enquiry are the only effectual agents against error." 
Raised in the Anglican church, Jefferson held some foundation for what he would accept in a theosophic context and that which he would leave open to rigorous scrutiny encouraged by the new paradigm of intellectual freedom. It is well known that he kept his personal religious views private. What he openly admired were ideas and the inspiration and inquiry that developed from them. Make no mistake, had he been born 200+ years earlier, he'd have most likely found himself bludgeoned by that same church if ever discovered altering text. He was a man who not only relished, but took full advantage of the intellectualism the Age of Enlightenment allowed.
Jefferson demonstrated in his cut and paste effort that the parables of Jesus are as meaningful and relevant to living an ethical and moral life without being attached to a divine source as are Aesop (approx. 620 and 560 BCE) and his fables, which also point to ethics and morals through the use of story. Jefferson's effort further suggests that there is immeasurable value in inquiry, and that well-being, both individually and collectively, may be achieved, indeed flourish, when unburdened of the extraneous interpretations of any singular theosophical text or world view.
References 1-2: Jefferson's Religious Beliefs at https://www.monticello.org/site/research-and-collections/jeffersons-religious-beliefs