SB 1.9 - Varṇāśrama dharma
Yudhiṣṭhira, in the presence of all the great sages, asked Bhīṣma about the essential principles of various religious duties. Kṛṣṇa inspired the king to ask questions to indicate that a devotee like Bhīṣma is superior to many great sages. Although Bhīṣma was in an aggrieved state, Kṛṣṇa wanted to prove that His pure devotees are always sound in body and mind by dint of spiritual enlightenment. The Lord declares emphatically that worship of His devotee is more valuable than worship of Himself.
Bhīṣma first defined all the classifications of castes and orders of life in terms of one’s qualifications (svabhāva). Then he systematically described counteraction by detachment and interaction by attachment. He described dharmas suitable for men according to their natures, according to varṇa and āśrama, which (āśrama) have qualities of renunciation and enjoyment described according to a person’s detachment and attachment. It is a rule that all the āśramas need not be undertaken one after the other by all the brāhmaṇas. If they have constant renunciation they become sannyāsīs and if they have constant attachment, they become gṛhasthas.