The man of knowledge must be ...

The man of knowledge must be able not only to love his enemies but also to hate his friends.
The man of knowledge must be able not only to love his enemies but also to hate his friends.

More phrases

If one does not know to which port one is sailing, no wind is favorable.
What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.
We are masters of the unsaid words, but slaves of those we let slip out.
I have always found that mercy bears richer fruits than strict justice.
A lie gets halfway around the world before the truth has a chance to get its pants on.

Quotes from the same author

Rejoicing in our joy, not suffering over our suffering, makes someone a friend.
You need chaos in your soul to give birth to a dancing star.
Love is blind; friendship closes its eyes.
We love life, not because we are used to living but because we are used to loving.
There is more wisdom in your body than in your deepest philosophy.