Below passage was given to me by one of my mentors when I was feeling very down about my volunteer work, where I was receiving a lot of criticism for the work I was doing. He mentioned that 'what you are doing is very rare, try to get more people like this to do' and gave this passage which was spoken by Theodore Roosevelt. Nelson Mandela was also inspired by this and gave it to his national sports teams.
It is not the critic who counts;
not the person who points out how the strong person stumbles,
or where the doer of deeds could have done them better.
The credit belongs to the person who is actually in the arena,
whose face is marred by dust and sweat and blood;
who strives valiantly; who errs,
who comes short again and again,
because there is no effort without error and shortcoming;
but who does actually strive to do the deeds;
who knows great enthusiasms, the great devotions;
who spend themselves in a worthy cause;
who at the best knows in the end the triumph of high achievement,
and who at the worst,
if they fail, at least fail while daring greatly,
so that their place shall never be with those cold and timid souls who neither know victory nor defeat.