Live your life as though your every act were to become a universal law.

...Act upon a maxim which, at the same time, involves its own universal validity for every rational being.

Live your life as though your every act were to become a universal law.

Two things fill the mind with renewed and increasing awe and reverence the more often and the more steadily that they are meditated on: the starry skies above me and the moral law inside me. I have not to search for them and conjecture them as though they were veiled in darkness or were in the transcendent region beyond my horizon; I see them before me and connect them directly with the consciousness of my existence

It must be freely admitted that there is a sort of circle here from which it seems impossible to escape. In the order of efficient causes we assume ourselves free, in order that in the order of ends we may conceive ourselves as subject to these laws because we have attributed to ourselves freedom of will; for freedom and self-legislation of will are both autonomy...

Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end.