"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."

This means no established state church, e.g. Church of England, and guaranteed freedom of religion.

1A has been fully incorporated, i.e. made applicable to state governments, under Everson v. Board of Education, 330 U.S. 1 (1947), Hamilton v. Regents of the University of California, 293 U.S. 245 (1934), Cantwell v. Connecticut, 310 U.S. 296 (1940), etc.

Note that this text does not contain the words "separation of church and state," nor the words "freedom from religion."