“Sharing is a kinsman's or a friend's obligation, and it is not in the category of a gift.”

Speech at Eureka College (1997)

Martí : Thoughts/Pensamientos (1994)
Context: Talent is a gift that brings with it an obligation to serve the world, and not ourselves, for it is not of our making. To use for our exclusive benefit what is not ours is theft. Culture, which makes talent shine, is not completely ours either, nor can we place it solely at our disposal. Rather, it belongs mainly to our country, which gave it to us, and to humanity, from which we receive it as a birthright. A selfish man is a thief.

Source: Two Boys Kissing

As quoted in Lives and Opinions of Eminent Philosophers, "Pythagoras", Sect. 10

Draft for a Statement of Human Obligation (1943)
Context: Anyone whose attention and love are really directed towards the reality outside the world recognizes at the same time that he is bound, both in public and private life, by the single and permanent obligation to remedy, according to his responsibilities and to the extent of his power, all the privations of soul and body which are liable to destroy or damage the earthly life of any human being whatsoever.
This obligation cannot legitimately be held to be limited by the insufficiency of power or the nature of the responsibilities until everything possible has been done to explain the necessity of the limitation to those who will suffer by it; the explanation must be completely truthful and must be such as to make it possible for them to acknowledge the necessity.
No combination of circumstances ever cancels this obligation. If there are circumstances which seem to cancel it as regards a certain man or category of men, they impose it in fact all the more imperatively.
The thought of this obligation is present to all men, but in very different forms and in very varying degrees of clarity. Some men are more and some are less inclined to accept — or to refuse — it as their rule of conduct.

Source: You Are Worthless: Depressing Nuggets of Wisdom Sure to Ruin Your Day