At Mahārāja Yudhiṣṭhira’s inquiry, Bhīṣmadeva first defined all the classifications of castes and orders of life in terms of the individual’s qualifications. Then he systematically, in twofold divisions, described counteraction by detachment and interaction by attachment.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
पुरुषस्वभावविहितान् यथावर्णं यथाश्रमम् । वैराग्यरागोपाधिभ्यामाम्नातोभयलक्षणान्
puruṣasvabhāvavihitān yathāvarṇaṃ yathāśramam | vairāgyarāgopādhibhyāmāmnātobhayalakṣaṇān
SB 1.9.26