“The enemy of my enemy is my friend.”

“Without the determination to win, a war is bound to be lost.”

“Our world is full of threats to nuclear weapons. People who are fanatical but know nothing about morality. We know more about war than peace, and we are better at killing than saving lives."

"In war, second place is none. Rewarding."

"Success is not the end, failure is not the end, only courage is eternal."

Etc.

They are all in Call of Duty.