Credited to William Cowper by Charles H. Spurgeon in Commenting and Commentaries. I have not located the original source.
A critic on the sacred text should be
Candid and learn’d, dispassionate and free;
Free from the wayward bias bigots feel,
From fancy’s influence and intemperate zeal;
For of all arts sagacious dupes invent,
To cheat themselves and gain the world’s assent,
The worst is—Scripture warped from its intent.