The gate at the entrance to auschwitz states “abreit macht frei” which means “work will set you free.” what did this mean to the prisoners?

I'm assuming that the Prisoners thought this meant that if they worked hard enough they would be set free from the prison. Although this was not the case and many of them died there. 

That meant that if they worked hard and did what they were told that they would be set free. But we know that it was a lie because they did not let them go they either killed them or kept them to work longer

Sponge bob ate the crab