A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose.
Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.
It is not necessary that whilst I live I live happily; but it is necessary that so long as I live I should live honourably.
Man must be disciplined, for he is by nature raw and wild.
Two things fill the mind with ever new and increasing wonder and awe - the starry heavens above me and the moral law within me.
What can I know? What ought I to do? What can I hope?