inelastic

epäelastinen, joustamaton lacking elasticity; inflexible, unyielding
1852, Nathaniel Hawthorne, The Blithedale Romance

He spoke languidly, and only those few words, like a watch with an inelastic spring, that just ticks a moment or two and stops again.

I cannot believe that Christ himself intended that his religion should be so inelastic, so hard and fast, so cruel as you imply.