Green’s Dictionary of Slang

come-to-Jesus adj.

(orig. US tramp) insincerely pious.

[[US]Lincoln Co. Leader (NM) 24 July 1/4: We have the Salvation Army with its ‘come-to-Jesus-Jane’ [...] and ‘Devil-Driver Sal’.
[US]J.T. Farrell ‘A Casual Incident’ in Short Stories (1937) 140: A small, nondescript crowd [...] listening while a sleek Greek conducted a Come-to-Jesus meeting.
[US]‘Dean Stiff’ Milk and Honey Route 202: Come to Jesus – A come-to-Jesus manner means to feign piety.
[Aus]N. Lindsay Age Of Consent 114: I’d have it out with him, I would, the dirty Come-to-Jesus skinflint.
[SA]A. Fugard No-Good Friday (1993) 50: You think we’re just poor suffering come-to-Jesus-at-the-end-of-it-all black men.

In compounds

come-to-Jesus coat (n.) [as worn by, inter alia, ministers and preachers]

(US) a frock coat.

[US]Monteleone Criminal Sl. (rev. edn).
come-to-Jesus collar (n.) [the preference for such collars among revivalist preachers]

(Can./US) a stiff dress collar.

[US]J. Tully Beggars of Life 242: The good man wore a ‘come-to-Jesus’ collar, a shoe string black tie and a Uriah Heep expression.
[US]‘Dean Stiff’ Milk and Honey Route 202: A come-to-Jesus collar is one worn by a preacher.
[US]Monteleone Criminal Sl. (rev. edn).