Kaṭha Upaniṣad 81

81

"tayoḥ, śreya ādadanasya sādhu bhavati hīyate 'rthādya u preyo vṛṇīte" (KaU 2.1) ity uktaṃ tatkasmāt ? yato dūraṃ dūreṇa mahatāntareṇaite viparīta anyonyavyāvṛttarūpe vivekāvivekātmakatvāt tamaḥprakāśāv iva viṣūcī viṣūcyau nānāgatī bhinnaphale saṃsāramokṣahetutvenety etat / ke ta ity ucyate -- yā cāvidyā preyoviṣayā vidyeti ca śreyoviṣayā jñātā nirjñātāvagatā paṇḍitais tatra vidyābhīpsinaṃ vidyārthinaṃ naciketasaṃ tvām ahaṃ manye / kasmād yasmād avidvad buddhipralobhinaḥ kāmā apsaraḥprabhṛtayo bahavo 'pi tvā tvāṃ nālolupanta na vicchedaṃ kṛtavantaḥ śreyomārgād ātmopabhogābhivāñchāsampādanena / ato vidyārthinaṃ śreyobhājanaṃ manya ity abhiprāyaḥ ///1,2.4 //

Shankara’s Commentary:
Com.—It has been stated that he who, of these pursues the good, attains the good and he that pursues the pleasant forfeits consummation; why is that so? Because, these two travel at a great distance from each-other, being mutually exclusive as they are of the nature of knowledge and ignorance, like light and darkness going different ways, i.e., leading to different results, being the cause of bondage and emancipation. What are these two is explained. Ignorance which, deals with ‘the pleasant’ and knowledge which deals with ‘the good,’ both well understood by the intelligent; here, I regard you Nachiketas, as longings after knowledge, because objects of desire the nymphs and the rest—which tempt the intellect of the ignorant, have not, though numerous, shaken thee, i.e., diverted thee from the path of ‘the good, by creating in you a desire for worldly enjoyment. Therefore, I regards you as longing after knowledge and worthy of attaining ‘the good.’ This is the drift.