《周书·列传·卷二十三》
等到把玉石剖开使它显露晶莹，让骏马飞驰来验试它的本领，这样美玉和石头、骏马和劣马才能分辨清楚。
及其剖而莹之，驰而试之，玉石驽骥，然后始分。
Wait until the jade is cut open to reveal its crystal clear, let the steed gallop to test its ability, so that the jade and stone, the steed and the inferior horse can be distinguished.