You cannot get blood out of a stone.

Understand the thought

Meaning in plain English

You cannot obtain something from a person or resource that does not have it to give. More pressure will not overcome a genuine lack of capacity.

What the words are saying

A stone has no blood to yield. The impossible demand becomes an image of trying to extract money, effort or information where the necessary resource is absent. The saying can help distinguish unwillingness from inability and make an expectation realistic. If someone has reached a practical limit, repeated demands may cause distress without producing the requested result. Before reaching that conclusion, establish what the actual limit is. The proverb should not be an easy excuse for avoiding a responsibility that could be met through a different method, more time or appropriate support.

Everyday example

A organiser stops asking a volunteer for additional hours after learning that she already has two caring commitments and no spare time.

When to use it

Use it when a demand exceeds an established and genuine capacity.

Agent-assisted editorial interpretation. This explains the words; it does not by itself verify their author or earliest origin.