白发丹心

Explanation: Loyalty: sincere heart. Describe the aging old, still cherish a sincere heart. 　　Source: "Han Su Wu Chuan" records envoy Wu Su Hun, taken nineteen years, a loyalty, and also, the story of hair and beard were white. 　　Examples: Although Rongfu shepherd rode, ~ do Hanchen. (Du Mu "He Huang" Poetry)