I think when Thucydides says: "They resigned to hope their unknown chance of happiness; but in the face of death they resolved to rely upon themselves alone." he invokes the exact same lesson learned over two millennia later by this author, Tadeusz Borowski:
"It is hope that makes people walk apathetically into the gas chamber, makes them shrink back from uprising ... Hope that tears apart family bonds, makes mothers reject their children, makes women sell themselves for a piece of bread and turns men into killers. Hope makes them fight for each day of life, for maybe the next day will bring liberation ... We did not learn to renounce hope, and that is why we died in the gas."
The soldiers of Athens, says Thucydides, made a distinction between a hope and action. Hope, they reserved for the chance of personal happiness. For the survival and flourishing of their community, they opted for action, putting the luxury of hope aside.
Timely statements from an ancient source, and one worth contemplating this year.