What does the First Amendment to the United States Constitution say?

According to Wikipedia, it says this:

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.[1]

I can’t understand how people can say that the Constitution is of supreme importance, but there should be restrictions on where mosques are built. I can understand people who don’t respect the Constitution saying that, but not those that do.