Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 16

Sanskrit:

एवं विधो ब्रह्मचारी वानप्रस्थो यतिर्गृही ।चरन्विदितविज्ञान: परं ब्रह्माधिगच्छति ॥ १६ ॥

ITRANS:

evaṁ vidho brahmacārīvānaprastho yatir gṛhīcaran vidita-vijñānaḥparaṁ brahmādhigacchati

Translation:

By practicing in this way, whether one be in the brahmacārī-āśrama, gṛhastha-āśrama, vānaprastha-āśrama or sannyāsa-āśrama, one must always realize the all-pervading presence of the Supreme Lord, for in this way it is possible to understand the Absolute Truth.

Purport:

This is the beginning of self-realization. One must first understand how Brahman is present everywhere and how He is acting. This education is called brahma-jijñāsā and is the real concern of human life. Without such knowledge, one cannot claim to be a human being; rather, he remains in the animal kingdom. As it is said, sa eva go-kharaḥ: without such knowledge, one is no better than a cow or an ass.