Walking on

'Sentries and cardboard shields: parallel gestures,

it seemed, in a world of bombing planes and motor traffic.

But perhaps the making of the gesture was what mattered.

She pulled herself together and walked on.'

From The First Day of Spring by Jan Struther.

On being able to accept that 

you are unable to right all the world's ills

but that you must do what you feel you can

and then walk on.