The law of humanity ought to ...

The law of humanity ought to be composed of the past, the present, and the future, that we bear within us; whoever possesses but one of these terms, has but a fragment of the law of the moral world.
 Edgar Quinet

Quotes from the same author

I mistrust the satisfaction which makes a display of the possession of Infinity; that is called fatuity in philosophic terms.
 Edgar Quinet