It is seldom very hard to do one's duty when one knows what it is, but it is often exceedingly difficult to find this out.

It is seldom very hard to do one's duty when one knows what it is, but it is often exceedingly difficult to find this out.

当一个人知道自己的职责是什么时，他很少很难去履行它，但要发现这一点往往是极其困难的。

-- Samuel Butler 塞缪尔巴特勒