He will often have to scratch his head, and bite his nails to the quick. [To succeed he will have to puzzle his brains and work hard.]
I beseech you to treasure up in your hearts these my parting words: Be ashamed to die until you have won some victory for humanity.
There is nothing hard inside the olive; nothing hard outside the nut.
Tomorrow do thy worst, for I have lived today.
Be brief, that the mind may catch thy precepts, and the more easily retain them.
Better one thorn pluck'd out than all remain.