Mandukya Karika, verse 3.16


आश्रमास्त्रिविधा हीनमध्यमोत्कृष्टदृष्टयः ।
उपासनोपदिष्टेयं तदर्थमनुकम्पया ॥ १६ ॥

āśramāstrividhā hīnamadhyamotkṛṣṭadṛṣṭayaḥ |
upāsanopadiṣṭeyaṃ tadarthamanukampayā || 16 ||

16. There are three stages of life corresponding to three,—the lower, the middle and the high—powers of comprehension. The Scripture, out of compassion, has taught this devotion (or discipline) for the benefit of those (who are not yet enlightened).

Shankara Bhashya (commentary)

(Objection)—If according to such Śruti passages as “Ātman is one and without a second”, etc., the Ātman alone, the one, the eternally pure, illumined and free, is the highest and the ultimate Reality and all else is unreal, what then is the purpose of the devotion and spiritual practices implied in such Śruti 1 passages as “Oh dear, Ātman alone is to be seen”, “The Ātman who is free from”, “He desired”, “It should be worshipped as Ātman”, etc.? Further, what is the utility of Karma (Vedic works) like Agnihotra, etc.? (Reply)—Yes, listen to the reasons. Āśrama signifies those who are competent to follow the disciplines of life as prescribed for the different stages.2 The word (in the text) also includes those who belong to the (different) castes3 and therefore who observe the rites (prescribed for those castes). The application of the word “Āśrama” implies that these castes are also three in number. How? It is because they are endowed with three kinds of intellect, viz., low,4 middle5 and high.6 This discipline as well as the (various) Karmas (works) are prescribed for the Āśramis of low and average intellect, by the Śruti, out of compassion, so that they also, following the correct disciplines, may attain to the superior knowledge. That7 this discipline is not for those who possess the right understanding, i.e., who are already endowed with the Knowledge of Ātman which is one and without a second, is supported by such Śruíi passages as “That which cannot be known by the mind, but by which, they say, the mind is able to think, that alone know to be Brahman, and not that which people here adore”, “That thou art”, “All this is verily Ātman”, etc. In the previous Kārikās it has been proved that the Scriptural statements regarding creation, etc., do not conflict with the nondual Ātman. This Kārikā states that the prescription of various disciplines associated with different Varṇas and Āśramas also does not contradict the view of the non-dual Ātman. The statements regarding creation, etc., as well as the various spiritual disciplines are only meant for the unenlightened in order to assist them to understand the oneness of Ātman.