Words to Live by: Seneca
So, so true.
Full quote:
Indeed I desire to transfer every one (books) to you; part of my joy in learning is that it puts me in a position to teach; nothing, hoever outstanding and however helpful, will ever give me any pleasure if the knowledge is to be for my benefit aline. If wisdom were offered me on the one condition that I should keep it shut away and not divulge to anyone, I should reject it. There is no possession of anything valuable unless one has someone to share it with.
Lucius Annaeus Seneca (Seneca the Younger), letters of a stoic, letter VI to Lucilius