The Republic by Plato Part 5 Page 52

before, when any one is well or ill, the universal word will be ‘with me it is well’ or ‘it is ill.’

Most true.

And agreeably to this mode of thinking and speaking, were we not saying that they will have their pleasures and pains in common?

Yes, and so they will.

And they will have a common interest in the same thing which they will alike call ‘my own,’ and having this common interest they will have a common feeling of pleasure and pain?

Yes, far more so than in other States.

And the reason of this, over and above the general constitution of the State, will be that the guardians will have a community of women and children?