先生曰：「今为吾所谓『格物』之学者，尚多流于口耳。况为口耳之学者，能反于此乎？天理、人欲，其精微必时时用力省察克治，方日渐有见。如今一说话之间，虽只讲天理，不知心中倏忽之间，已有多少私欲。盖有窃发而不知者，虽用力察之，尚不易见，况徒口讲而可得尽知乎？今只管讲天理来顿放著不循，讲人欲来顿放著不去，岂『格物』、『致知』之学？后世之学，其极至，只做得个『义袭而取』的工夫。」
先生说：「如今从事我所谓『格物』之学的人，尚且多流于口耳之学。何况那些本来就在做口耳之学的人，能回头到这里吗？天理人欲的精微，必须时时用力省察克治，才会日渐有所见。如今在一说话之间，虽然口里讲着天理，不知心中倏忽之间已起了多少私欲。有悄悄萌发而不自知的，用力体察尚且不易发现，何况光凭口讲就能完全知晓吗？如今只管讲天理却又放着不去遵循，讲人欲却又放着不去铲除，这算什么『格物』『致知』之学？后世之学到极处，也只做得个『义袭而取』的功夫。」
The Master said: 'Even those now studying what I call the investigation of things mostly let it slip into learning of mouth and ear. How much less can those already sunk in mouth-and-ear learning turn back to this! The fineness of heavenly principle and human desire is seen only by ceaseless examination and mastery. Even while one speaks, mouth full of heavenly principle, who knows how many selfish desires have sprung up in a flash of the heart? Some steal forth unnoticed; even forceful scrutiny hardly finds them — can mere talk know them all? To lecture on principle yet not follow it, lecture on desire yet not remove it — is that the learning of investigating things and extending knowledge? Later learning at its best accomplishes only a righteousness snatched by surprise assault.'