《北史·列传·卷二十二》
文明皇后说： 六军出发，如惊雷电闪，势同摧枯拉朽，何必担心有四难题呢？ 
文明太后曰： 六军电发，有若摧朽，何虑四难也。 
Empress Wenming said: The six armies set off like thunder and lightning, and they are like destroying the dead and pulling the decayed. Why worry about four problems?