From George Will, here:
George Washington famously would not kneel to pray. And when his pastor rebuked him for setting a bad example by leaving services before communion, Washington mended his ways in his characteristically austere manner: He stayed away from church on communion Sundays. He acknowledged Christianity's "benign influence" on society, but no ministers were present and no prayers were said when he died a stoic's death. This, even though Washington had proclaimed in his famous Farewell Address (which to this day is read aloud in Congress every year on his birthday) that "religion and morality are indispensable supports" for "political prosperity." He said, "Let us with caution indulge the supposition that morality can be maintained without religion." He warned that "reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle."