The R-1 classification applies to a religious worker. This is a foreign national coming to the U.S. temporarily to work:
The applicant (religious worker) must have been a member of a religious denomination having a nonprofit religious organization in the United States for at least the two years immediately prior to the application date. To be eligible, the U.S. petitioning organization must be a nonprofit religious organization granted (or eligible for) tax exempt status, and must demonstrate that it can and will provide for all of the R-1 beneficiary’s financial and physical needs.
If the foreign national is outside the U.S., he or she may apply directly at a US Consulate for an R visa. If visa exempt (only applies to Canadians), the foreign national may apply at a port of entry.
If the foreign national is inside the U.S., the religious organization may use the I-129 to petition for a change of status, extension of stay, or change in the previously approved terms and conditions of employment.