The worst is that the very ...

The worst is that the very hardest thinking will not bring thoughts. They must come like good children of God and cry, \
The worst is that the very hardest thinking will not bring thoughts. They must come like good children of God and cry, "Here we are." You expend effort and energy thinking hard. Then, after you have given up, they come sauntering in with their hands in their pockets. If the effort had not been made to open the door, however, who knows when they could have come.

Quotes from the same author

Knowing is not enough; we must apply. Willing is not enough; we must do.
Just trust yourself, then you will know how to live.
The really unhappy person is the one who leaves undone what they can do, and starts doing what they don't understand; no wonder they come to grief.
What is not started today is never finished tomorrow.
A man sees in the world what he carries in his heart.