The Christian god can easily be pictured as virtually the same god as the many ancient gods of past civilizations. The Christian god is a three headed monster; cruel, vengeful and capricious. If one wishes to know more of this raging, three headed beast-like god, one only needs to look at the caliber of people who say they serve him. They are always of two classes: fools and hypocrites.
Source, in full
See the Positive Atheism site on the extreme unlikelihood of this quote being authentic. It actually contains some known phrases of Jefferson's, but they are compounded with almost certainly false statements into a highly misrepresentative whole. Jefferson's own opinions on Jesus, God, Christianity and general opinions about them were far more complex than is indicated in this statement.