I found this letter on a great site I visit often (WWW.LETTERSOFNOTE.COM). You can go to the site for an explanation of why he wrote it. For some reason I find it his words here striking and they cause me to think about our place in things. I've read it several times and still wonder what he was saying, you can take it as his support or opposition towards religion... I think.
It reads as follows:
February 12, 1950
Dear Mr. Marcus:
A human being is a part of the whole, called by us "Universe", a part limited in time and space. He experiences himself, his thoughts and feelings as something separated from the rest — a kind of optical delusion of his consciousness. The striving to free oneself from this delusion is the one issue of true religion. Not to nourish the delusion but to try to overcome it is the way to reach the attainable measure of peace of mind.
With my best wishes,
sincerely yours,
Albert Einstein.