I think vital Religion has always suffer'd, when Orthodoxy is more regarded than Virtue. And the Scripture assures me, that at the last Day, we shall not be examined [on] what we thought, but what we did; and our Recommendation will not be that we said Lord, Lord, but that we did good to our Fellow Creatures. See Matth. 26.Letter to Josiah and Abiah Franklin, April 13, 1738, quoted in The Founders on Religion: A Book of Quotations, edited by James H. button (Princeton: 2005), pg. 80. Interestingly enough, Franklin doesn't evidence a hostility for orthodoxy per se, simply orthodoxy that detracts from the cultivation of right conduct. Works were at the center of true religion for Franklin -- not to the exclusion of belief in God, but as the foundation for how to determine if that belief was authentic. And he cited to the Christian New Testament in support of his approach. This balanced approach to belief & works appears in Franklin's most well-developed articulation of his religious convictions, found in his Autobiography. This articulation he referred to as "an intended Creed, continuing as I thought the Essentials of every known Religion, and being free of every thing that might shock the Professors of any Religion":
That there is one God who made all things. That he governs the World by his Providence. That he ought to be worshipped by Adoration, Prayer and Thanksgiving. But that the most acceptable Service of God is doing good to Man. That the Soul is immortal. And that God will certainly reward Virtue and punish Vice either here or hereafter.Franklin's views on religious belief & the necessity of works are thus remarkably consistent over time, and far from evidencing a hostility or apathy towards religious life, manifests a concern that religion -- belief in a God who is an active creator & governor of the world -- must manifest itself in the life of the individual. While Franklin's creed is not expressly Christian (and was not intended to be), it certainly is not incompatible with orthodox Christianity. Franklin's creed could be affirmed, with perhaps only a minor quibble, by a Roman Catholic, for example, who steadfastly held to the decrees of the Council of Trent. And it would be completely consonant with the faith of Christian unitarians like John & Abigail Adams.
Franklin's statement of belief should put to rest any talk of him not being a theist. His God is no absentee landlord, but is an active presence in the world, who not only creates but "governs the World" via divine Providence. This God is worthy of worship -- including prayer and thanksgiving, indicating that Franklin believed that God acted in the lives of individual people -- hence the benefit of asking God for help (through prayer) and thanking Him for His blessings. Most touchingly to me, Franklin insists on the importance of good works in human life. The best way to serve this God is through good works, and that the judgment of each person's immortal soul will be based on what he or she has done in this life.
While not a regular churchgoer like Washington, or a Hebrew scholar like Madison, Franklin -- who attended no church regularly nor could read any biblical languages -- left a far clearer statement of faith than virtually any of the other major founders, Jefferson included. And it was a statement of faith that affirmed an active, providential Creator deity, a deity who would sit in judgment upon all human beings, rewarding and punishing them according to the deeds they did in this life.