Full Idea
In a communist society we shall have an association, in which the free development of each is the condition for the free development of all.
Gist of Idea
The free development of each should be the condition for the free development of all
Source
K Marx / F Engels (The Communist Manifesto [1848], §2)
Book Reference
Marx,K./Engels,F.: 'The Communist Manifesto', ed/tr. Taylor,A.J.P. [Penguin 1973], p.105
A Reaction
This ringing slogan is remarkably close to John Stuart Mill's defence of liberalism, where liberty is an absolute, as long as it avoids the liberty of others. Personally I think freedom is marginal in political philosophy, like food and shelter.