《贞观政要·卷四·尊敬师傅》
太子虽然年轻气盛，有充分的时间修养性情，但我实在担心随着岁月的流逝，他荒废了学业，引起讥谤，安逸之风从此开始。我见识短小，有幸侍奉太子，想要使太子思虑开阔，使其在不久的将来闻名四方。我不敢故意陈述旧事，只是希望以陛下的圣明为例来作为说明。
虽富于春秋，饬躬有渐，实恐岁月易往，堕业兴讥，取适晏安，言从此始，臣以愚短，幸参侍从，思广储明，暂愿闻彻，不敢曲陈故事，切请以圣德言之。
The crown prince, though young and high-spirited, has ample time to cultivate his character, but I fear that as the years pass, he will neglect his studies and invite criticism, and that the seeds of indolence will take root. My understanding is limited, but I have the good fortune to serve as the crown prince's tutor, and I wish to broaden his thinking, so that in the not-too-distant future he will be renowned throughout the realm. I do not presume to dwell on past events, but I would like to use your Majesty's own illustrious example to make my point.