In his "Metaphysics of Morals", published in 1784, Kant discussed the singular right with which all men are endowed upon birth: freedom. It is this right which gives us equality, but from that single right nature demands we develop differently from that point forward, seeking out Kant's famous "ends."
The first sentence of the quote is the most famous portion.
"Freedom is independence of the compulsory will of another; and in so far as it can coexist with the freedom of all according to a universal law, it is the one sole original, inborn right belonging to every man in virtue of his humanity. There is, indeed, an innate equality belonging to every man which consists in his right to be independent of being bound by others to anything more than that to which he may also reciprocally bind them. It is, consequently, the inborn quality of every man in virtue of which he ought to be his own master by right (sui juris). There is, also, the natural quality of justness attributable to a man as naturally of unimpeachable right (justi), because be has done no wrong to any one prior to his own juridical actions. And, further, there is also the innate right of common action on the part of every man, so that he may do towards others what does not infringe their rights or take away anything that is theirs unless they are willing to appropriate it; such merely to communicate thought, to narrate anything, or to promise something whether truly and honestly, or untruly and dishonestly (veriloquim aut falsiloquim), for it rests entirely upon these others whether they will believe or trust in it or not. But all these rights or titles are already included in the principle of innate freedom, and are not really distinguished from it, even as dividing members under a higher species of right."-Immanuel Kant