They say that "An ounce of praise is worth a ton of criticism". In case you are a bit scratchy on old imperial weights and measures, I have done the calculation for you and (assuming that whoever made the original measurement was using long tons and avoirdupois ounces rather than troy ounces) it works out that praise is 35,840 times more effective than criticism. While the logic can be demonstrated in many contexts - from bringing up children to dealing with paid staff - it is especially true in volunteer organizations.
Dishing out praise for jobs well done is not something I'm good at. This was brought home to me last Sunday when somebody enthusiastically praised me for something I had done. I was quite chuffed. I generally get my satisfaction from doing jobs to a standard that pleases me - jobs that most other people don't even notice need doing - let alone when they have been done.
I'm the sort of person who doesn't generally put much store on other people's comments but I realise that not everybody else is built like me. (Just as well). So if you appreciate something being done around the place, preaching a sermon, "singing in the choir", mowing the lawn or 'just' sweeping the floor and picking up the rubbish, let whoever is doing it, know.
(It may be that we should 'metricate' the saying to "A gram of praise is worth a tonne of criticism"; the ratio then becomes a million to 1.)