The full, non-slogan version of Nozick’s “entitlement theory” of justice, expressed roughly in an extended version of the classic form:
From each according to what he chooses to do, to each according to what he makes for himself (perhaps with the contracted aid of others) and what others choose to do for him and choose to give him of what they’ve been given previously (under this maxim) and haven’t yet expended or transferred.
Robert Nozick, Anarchy, State And Utopia (1974), Ch. 7: Distributive Justice, Section I, Patterning.