चतुर्युगाख्यान (Caturyuga-Ākhyāna) — Yuga-wise Origins and Measurements of Beings
विद्यायाः साधनात्साधुर्ब्रह्मचारी गुरोर्हितः / गृहाणां साधनाच्चैव गृहस्थः साधुरुच्यते
vidyāyāḥ sādhanātsādhurbrahmacārī gurorhitaḥ / gṛhāṇāṃ sādhanāccaiva gṛhasthaḥ sādhurucyate
By the discipline of learning, the brahmacārin who acts for the guru’s good is called a sādhū; and by the discipline of household duties, the householder too is called a sādhū.