"Fight with a happy heart."
Before heading into Iraq in 2003, all Marines of the 1st Marine Division received a letter from General Mattis.
In the letter, he spoke candidly to his troops, telling them "we will move swiftly and aggressively against those who resist, we will treat others with decency, demonstrating chivalry and soldierly compassion for people who have endured a lifetime under Saddam's oppression."