Mill distinguishes between the intention of an act, which determines its morality, and the motive of the agent, which informs our estimation of the agent's character.
Chapter III: OF THE ULTIMATE SANCTION OF THE PRINCIPLE OF UTILITY.

Mill discusses the necessity of identifying the 'sanction' or binding force of any moral standard, noting that this challenge applies to all ethical systems.

Mill discusses the psychological difficulty of moving from customary, felt moral obligations to abstract general principles, noting that people often question why they should prioritize general happiness over their own.

The author identifies the external sanctions of utilitarianism as the hope for favor and fear of displeasure from fellow humans or a divine being, coupled with natural sympathy.

The text defines the internal sanction of duty as a subjective feeling or 'conscience' that, while often encrusted with various social and religious associations, manifests as a painful shrinking from the violation of moral principles.