《资治通鉴·隋纪·隋纪三》
文帝本性崇尚节俭，杨勇曾经在已经很精美华丽的蜀地出的铠甲上再加装饰，文帝看到后很不高兴，他告诫杨勇说： 自古以来帝王无一喜好奢侈而能长久的，你作为皇位继承人，应当以节俭为先，这样才能承继宗庙。
上性节俭，勇尝文饰蜀铠，上见而不悦，戒之曰： 自古帝王未有好奢侈而能久长者。汝为储后，当以俭约为先，乃能奉承宗庙。
Emperor Wen exalted frugality, once Yang dressed beautifully embroidered body armor, Emperor Wen was very upset, and warned Yang Yong: Since ancient times, no emperor who liked luxury can last, as the crown prince, should live frugally, to inherit the family business.