Friedrich Nietzsche

The Gay science

26 What is life? – Life – that is: continually shedding something that wants to die; Life – that is: being cruel and inexorable against anything that is growing weak and old in us, and not just in us. Life – therefore means: being devoid of respect for the dying, the wretched, the aged? Always being a murderer? And yet old Moses said: ‘Thou shalt not kill.’