26 CFR 1.1402(e)-4A: (e)-4A Period for which exemption is effective.

(a) In general. If an application for exemption on Form 4361:

(1) Is filed by a minister, a member of a religious order, or a Christian Science practitioner eligible to file such an application (see particularly paragraph (a) (2) and (3) of § 1.1402(e)-2A), and

(2) Is approved (see paragraph (c) of § 1.1402(e)-2A),

the exemption from the tax on self-employment income shall be effective for the first taxable year ending after 1967 for which such minister, member, or practitioner has net earnings from self-employment of $400 or more any part of which was derived from the performance of service in his capacity as a minister, member, or practitioner, and for all succeeding taxable years. See, however, paragraphs (b)(1)(ii) and (d)(2) of § 1.1402(c)-5 relating to ministers and members of religious orders and paragraph (b)(2) of § 1.1402(c)-6 relating to Christian Science practitioners.

(b) Exemption irrevocable. An exemption granted to a minister, a member of a religious order, or a Christian Science practitioner pursuant to the provisions of section 1402(e) is irrevocable.