Full Idea
Force precedes morality; for a time morality itself is force, to which others acquiesce. Later it becomes custom, and then free obedience, and finally almost instinct; then it is coupled to pleasure, like all habitual things, and is now called 'virtue'.
Gist of Idea
First morality is force, then custom, then acceptance, then instinct, then a pleasure - and finally 'virtue'
Source
Friedrich Nietzsche (Human, All Too Human [1878], 099)
Book Reference
Nietzsche,Friedrich: 'Human, All Too Human', ed/tr. Faber,Marion [Penguin 1994], p.69
A Reaction
How few philosophers delve into the history of the concepts they work with, and yet how revealing it can be. Richard Taylor was wonderful on 'duty'. You will never grasp the 'problem of free will' if you don't examine its history.