Who said "In this world, your enemies are your greatest teachers."?

This quote is attributed to Tom Hagen.

In this world, your enemies are your greatest teachers. - Tom Hagen

"In this world, your enemies are your greatest teachers."

Tom Hagen Education

"I'm a consigliere, not a driver."

"Never discuss business with a mouth full of food."

"A lawyer with his briefcase can steal more than a hundred men with guns."

"The Don has plans for you."

"Education opens doors."

"Education opens doors to endless possibilities."

"I ain't got the education you got, bub."

"You can't put a price on history."