Yāska's Nirukta 3.7.1

3.7.1

āha-yadi nāmākhyātopasarganipātānāmaparihīnā śaktirdevānapyabhidhātum | atha kimarthaṃ vede mantraḥ samāmnātaḥ ? || ucyate- " puruṣavidyānityatvāt karmasampattirmantro vede " | puruṣeṣu manuṣyeṣu vidyāyāḥ vijñānasyānityatvāt puruṣavidyānityatvādaddhetoḥ karmasampattiḥ phalena sampādanam aviguṇakarmasampattiḥ, phalasampannameva karma bhaviṣyatītyevamarthaṃ vede mantraḥ ' samāmnātaḥ ' iti vākyaśeṣaḥ | itarathā hi puruṣeṣu vijñānasyānityatvādyathārthaṃ nābhidadhate devāścāmākhyātopasarganipātairaśikṣitatvānmandaśikṣitatvādvismaraṇaśīlatvādvā | devānāmaparādhyeyurayathāvatprayuñjānāḥ nāmākhyātopasarganipātān | tataśca sarvārthapratyakṣadṛśo devāḥ svalpamapyayathāvadabhidhānaṃ na marṣayanti viguṇametaditi | vidyā'nityatvāttadabhāve neyuḥ karmāṇa | tataśca devatāhīnaṃ karmaphalaṃ sampadyate | na ca kevalaṃ phalāsampattiḥ, || kiṃ tarhi ?, duritahetuko doṣo'pi syāt | tasmādeta eva nāmākhyātopasarganipātāḥ prayogānuparipāṭīniyamārthaṃ mantratvena vede samāmnātāḥ | nahi nāmākhyātopasarganipātāna parityajya mantrāḥ santi | etadeva caturvidhaṃ padajātaṃ prayogānuparipāṭyā kayācidavasthitaṃ mantrā ityucyante || āha-kathamanityatvaṃ vidyāyāḥ puruṣeṣviti ? | ucyate- iha yena vākyaviracanānukrameṇa arthamanvaneprepsyate, ' manuṣya evameva brūyāt- ' tvaṃ gantuṃ devadattam' iti | sa tenaiva vākyaviracanānukrameṇa baddhamapi mantamartha na śaknoti pratipādayitum | evamanityatvaṃ vidyāyāḥ puruṣeṣu | tadadoṣaṃ vā manuṣyāna prati, sarveṣāmeva manuṣyāṇāmānityatvādvidyāyāḥ |