Via the always useful Cornell Legal Information Institute.
(a) In general
Government shall not substantially burden a person’s exercise of religion even if the burden results from a rule of general applicability, except as provided in subsection (b) of this section.
(b) Exception
Government may substantially burden a person’s exercise of religion only if it demonstrates that application of the burden to the person—
(1) is in furtherance of a compelling governmental interest; and
(2) is the least restrictive means of furthering that compelling governmental interest.(c) Judicial relief
A person whose religious exercise has been burdened in violation of this section may assert that violation as a claim or defense in a judicial proceeding and obtain appropriate relief against a government. Standing to assert a claim or defense under this section shall be governed by the general rules of standing under article III of the Constitution.
Via the often useful Wikipedia.
The Free Exercise Clause of the First Amendment states that Congress shall not pass laws prohibiting the free exercise of religion. In the 1960s, the Supreme Court interpreted this as banning laws that burdened a person’s exercise of religion (e.g. Sherbert v. Verner, 374 U.S. 398 (1963); Wisconsin v. Yoder, 406 U.S. 205 (1972)). But in the 1980s the Court began to allow legislation that incidentally prohibited religiously mandatory activities as long as the ban was “generally applicable” to all citizens.
“Religiously mandatory activities” can mean a lot of things – such as refusing to seek medical treatment for a sick child, or murdering a daughter for perceived violations of rules governing sex, or killing all believers in a rival sect. A secular state shouldn’t be messing with the concept of “religiously mandatory activities” at all.