... knowledge must ...

... knowledge must continually be renewed by ceaseless effort, if it is not to be lost. It resembles a statue of marble which stands in the desert and is continually threatened with burial by the shifting sand. The hands of service must ever be at work, in order that the marble continue to lastingly shine in the sun. To these serving hands mine shall also belong.
... knowledge must continually be renewed by ceaseless effort, if it is not to be lost. It resembles a statue of marble which stands in the desert and is continually threatened with burial by the shifting sand. The hands of service must ever be at work, in order that the marble continue to lastingly shine in the sun. To these serving hands mine shall also belong.

Quotes from the same author

It is characteristic of the military mentality that non-human factors ... are held essential, while the human being, his desires and thoughts-in short, the psychological factors-are considered as unimportant and secondary.
In the middle of every difficulty lies opportunity.
You can't blame gravity for falling in love.
One may say the eternal mystery of the world is its comprehensibility.
The human spirit must prevail over technology.