"Congress shall make no law respecting the 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."
(In those days,
run-on sentences were the norm.)
As with many of the amendments of the Bill of Rights, the First focuses upon rights which had been violated by the British Crown during the colonial period. The Founders were concerned about these rights because they did not want the new nation to become just as oppressive as the colonial regime had been.
Almost immediately after the adoption of the Constitution, however, Congress began to violate these rights, beginning with the Sedition Act of 1798.