《旧唐书·列传·卷一百二十四》
 臣听说道行至高者莫过于广成、玄元，人间至圣者莫过于轩辕、孔子。
臣闻道之高者，莫如广成、玄元，人之圣者，莫若轩黄、孔子。
I have heard that those whose practice methods have reached great heights are none other than Guangcheng and Xuanyuan, and the greatest saints among humans are none other than Xuanyuan and Confucius.