1208
I don't know about holy but I definitely see it as the most important document in the American system of government (a Republic if we can keep it).
Literally all authority in America flows from our Constitution. The only reason the President is in charge is because the Constitution says so. The only reason laws passed by Congress are laws is because the Constitution says so. The only reason the judiciary exists as a place to go and settle disputes and apply the laws is because the Constitution says so.
Without the Constitution the only way society would run is by force.
I know that people with Gadsden flags and dog eared copies of Atlas Shrugged think that's how society works today, but it's not. But that's a whole other discussion.
We mostly just agree to abide by the laws which derive their legitimacy from Constitution. If it weren't there, we'd have no foundation. That's why it's like a holy document. Except it's better than a holy book, because there's no claim of infallibility. It is expected to be modified, and it has been modified.
Thomas Jefferson actually expected there to be constitutional conventions on a regular basis to rewrite the thing from time to time. A part of me thinks that might be a good idea. Maybe reconstitute the Congress as two proportional representation parliaments (one with single 8 year terms, one with unlimited 2 year terms or something, people vote for parties not people). Eventually abolish the Second Amendment or at least rewrite it to make it clear that "well regulated" is important, and there can be limits to personal armament. Expand the Fourth to cover modern data creation and storage. Do a better job with patents & copyright. On and on.