Maitrayaniya Upanishad 4.2.4

4.2.4

tyevamāśramadharmeṣvatiyatnaḥ kriyate tapasaiva brahmavidyodayasambhavāt "tapasā vindate" mahaditi vacanāditi cet, satyaṃ, tadapyāśramadharmāvirodhyeva sādhanaṃ na tadviruddhamapītyāśayenāha āśrameṣveveti | āśrameṣvanavastha evānāśramastha eva tapasvī vā dhārmiko vetyādyucyate yat tadetadayuktamiti yojanā | nanu tarhi tatra tatrātmajñānasādhaneṣu 'tapasā brahma vijijñāsakha' ityādi tapovidhānamanarthakaṃ, svadharmānuṣṭhānādevātmajñānasiddherityāśaṅkāyāmāha nātapaskasyeti | atapaskasya vaidhakāyaśoṣaṇarahitasyātmajñāne nādhigamo nādhigamanaṃ ātmajñānaṃ na prāpnotītyarthaḥ | na kevalametāvat kintu karmasiddhirvā karmaphalalābho vā tasya na syādityarthaḥ | asminnarthe sammatimiva ślokamudāharati, evaṃ hyāheti | tapasā svadharmācaraṇena tadavirodhidvaiṣṇavādiniṣkāmavrataviśeṣācaraṇalakṣaṇena ca sattvaṃ sattvaguṇapradhānaṃ cittaṃ prāpyate, viśuddhasattvatā labhyata ityarthaḥ | tasmāt sattvānmanaḥ samprāpyate, manute'neneti mano vivekavijñānaṃ, tasmānmanaso mananādātmā pūrṇaṃ tattvaṃ paraṃ brahma hi niścitaṃ prāpyate | ātmatattvasākṣātkāra evātmaprāptirnānyā tasyāptirnityā''ptasvarūpatvāt, ata ātmasākṣātkāro bhavatītyarthaḥ | ko'yamātmetyata āha