In order that people may be happy in their work, these three...

In order that people may be happy in their work, these three things are needed: They must be fit for it: they must not do too much of it: and they must have a sense of success in it - not a doubtful sense, such as needs some testimony of others for its confirmation, but a sure sense, or rather knowledge, that so much work has been done well, and fruitfully done, whatever the world may say or think about it.