《元史》中记载:宋元之际,世道纷乱。一天,学者许衡外出,因为天气炎热,口渴难耐,正好路边有一棵梨树,行人纷纷前去摘梨解渴,只有许衡不为所动。于是,有人就问他:“你为什么不去摘梨吃呢?”许衡回答道:“不是自己的梨,怎么可以随便乱摘呢?”那人就笑他迂腐:“现在兵荒马乱的,管它是谁的梨!说不定这梨树已经没有主人了。”许衡却回答道:“梨虽无主,我心有主。” “Yuan Shi” records: the occasion of the Song and Yuan Dynasties chaotic world. One day, the scholar Xu Heng went out because of the hot weather and thirsty. There was a pear tree on the roadside. Pedestrians went to pick pears and quench their thirst. Only Xu Heng was unmoved. So, someone asked him: “Why do not you pick pear to eat?” Xu Heng replied: “Not your own pears, how can you arbitrarily pick it?” “The man laughs at him pedantic: ” Now that the troops are in chaos and turmoil, whoever controls the pear? Perhaps this pear tree has no owner yet. “Xu Heng replied:” Although there is no Lord in the pear, I have the Lord in my heart. "