难能可贵

Explanation: Difficult to be: extremely difficult. Means not easy to do things actually can be very valuable. 　　Usage: Joint type; as object, attribute; with a compliment 　　Source: Song Su "Xunqing theory": "Zi Lu's courage, Zigong Debate, Ran wisdom, the three sons who are the world's so-called hard and valuable to those who are." 　　Examples: Mo is at it one has been able so small, is also ~ carry on. (Zhang Binglin, "Choi said zhuzixue")