A striking confirmation of this is furnished by those Christian writers of the last century who treat the >moral unbeliever as a fool who sacrifices his happiness both here and hereafter. These men were, for the most part, earnestly engaged in the practice of virtue, and yet this practice had not made them love virtue so much as to prefer it, even under ordinary circumstances, to the sensual and other enjoyments that it excludes. It seems then absurd to suppose that, in the case of persons who have not developed and strengthened by habit their virtuous impulses, the pain that might afterwards result from resisting the call of duty would always be sufficient to neutralise all other sources of pleasure.

ME Book 2 Chapter 5 Section 4