He was a deist at best, quite a few early presidents were, especially those who signed the Constitution.
The United States government must not undertake to run the Churches. When an individual, in the Church or out of it, becomes dangerous to the public interest he must be checked.
-- Abraham Lincoln, regarding the Churches, quoted from Franklin Steiner, The Religious Beliefs of Our Presidents, p. 143
"In religion, Mr. Lincoln was about of the same opinion as Bob Ingersoll, and there is no account of his ever having changed. He went to church a few times with his family while he was President, but so far as I have been able to find out, he remained an unbeliever. Mr. Lincoln in his younger days wrote a book, in which he endeavored to prove the fallacy of the plan of salvation and the divinity of Christ."
-- Judge James M Nelson, who had an intimate acquaintance with Lincoln in Washington, in the Louisville Times, in 1887, quoted from Franklin Steiner, The Religious Beleifs of Our Presidents, p. 137
"The measure of his difference from most of the men who surrounded him is best gauged by his attitude toward the fundamentals of religion. For all his devotion to his cause he did not allow himself to believe that he knew the mind of God with regard to it. He was never so much the mystic as in his later days and never so far removed from the dogmatist. Here was the final flowering of that mood which appears to have lain at the back of his mind from the beginning -- his complete conviction of a reality of a supernatural world joined with a belief that it was too deep for man to fathom. His refusal to accept the 'complicated' statement of doctrines which he rejected, carried with it a refusal to predicate the purpose of the Almighty. Again, that singular characteristic, his power to devote himself wholly to a cause and yet to do so in such a detached, unviolent way that one is tempted to call it passionless. He retained nothing of the tribal forms of religion and was silent when they raged about him with a thousand tongues."
-- Encyclopædia Britannica, 14th ed., quoted in Franklin Steiner, The Religious Views of Our Presidents, p. 139-40
Though this isn't quite my point, it takes nothing away from the fact that Mr. Davis is ignorant, and quite frankly kind of stupid.