Chandogya Upanishad (with commentary) · Chapter 7.18

ChUpBh_7,17.1 yadā vai satyaṃ paramārthato vijānātīdaṃ paramārthaḥ satyamiti, tato 'nṛtaṃ vikārajātaṃ vācārambhaṇaṃ hitvā sarvavikārāvasthaṃ sadevaikaṃ satyamiti tadevātha vadati yadvadati /
nanu vikāro 'pi satyameva /
"nāmarūpe satyaṃ tābhya mayaṃ prāṇaśchannaḥ" /
"prāṇā vai satyaṃ teṣāmeṣa satyam"iti śrutyantarāt /
satyamuktaṃ satyatvaṃ śrutyantare vikārasya na tu paramārthāpekṣamuktaṃ kiṃ tarhīndriyaviṣayatvāpekṣaṃ sacca tyacceti satyamityuktaṃ taddvāreṇa ca paramārthasatyasyopalabdhirvivakṣiteti /
prāṇā vai satyaṃ teṣāmeṣa satyamiti coktam /
ihāpi tadiṣṭameva /
iha tu praṇaviṣayātparamārthasatyavijñānābhimānādvyutthāpya nāradaṃ yatsadeva satyaṃ paramārthato bhūmākhyaṃ tadvijñāpayiṣyāmītyeṣa viśeṣato vivakṣitor'thaḥ /
nāvijānansatyaṃ vadati yastvavijānanvadati so 'gnyādiśabdenāgnyadīnparamārthasadrūpānmanyamāno vadati na tu te rūpatrayavyatirekeṇa paramārthaḥ santi /
tathā tānyapi rūpāṇi sadapekṣayā naiva santītyato nāvijānansatyaṃ vadati /
vijānanneva satyaṃ vadati /
na ca tatsatyavijñānamavijijñāsitamaprārthitaṃ jñāyata ityāha-vijñānaṃ tveva vijijñāsitavyamiti /
yadyevaṃ vijñānaṃ bhagavo vijijñāsa iti /
evaṃ satyādīnāṃ cottarottarāṇāṃ karotyantānāṃ pūrvapūrvahetutvaṃ vyākhyeyam //1//
iti cchāndogyopaniṣadi saptamādhyāyasya saptadaśaḥ khaṇḍaḥ
START ChUp 7,18.1
yadā vai manute 'tha vijānāti |
nāmatvā vijānāti |
matvaiva vijānāti |
matis tv eva vijijñāsitavyeti |
matiṃ bhagavo vijijñāsa iti