Who said "We must all conduct ourselves like soldiers."?

This quote is attributed to Michael Corleone.

We must all conduct ourselves like soldiers. - Michael Corleone

"We must all conduct ourselves like soldiers."

Michael Corleone Courage

"I'm gonna make him an offer he can't refuse."

"It's not personal, Sonny. It's strictly business."

"A man who doesn't spend time with his family can never be a real man."

"The things you own end up owning you."

"Never let fear stop you from chasing your dreams."

"Courage is being afraid but doing it anyway."

"Sometimes you gotta do what you gotta do."

"Sometimes you have to be the monster to stop the monsters."