Treat people as an end, and never as a means to an end - Immanuel Kant

What then is it which justifies virtue or the morally good disposition, in making such lofty claims? It is nothing less than the privilege it secures to the rational being of participating in the giving of universal laws, by which it qualifies him to be a member of a possible kingdom of ends, a privilege to which he was already destined by his own nature as being an end in himself, and on that account legislating in the kingdom of ends; free as regards all laws of physical nature, and obeying those only which he himself gives, and by which his maxims can belong to a system of universal law, to which at the same time he submits himself. For nothing has any worth except what the law assigns it.

Act so as to treat humanity, whether in your own person or in that of another, at all times also as an end, and not only as a means.

All natural capacities of a creature are destined to evolve completely to their natural end.