SB 11.18.42

bhikṣor dharmaḥ śamo ’hiṁsā
 tapa īkṣā vanaukasaḥ
gṛhiṇo bhūta-rakṣejyā
 dvijasyācārya-sevanam
Synonyms: 
bhikṣoḥ — of a sannyāsī; dharmaḥ — the main religious principle; śamaḥ — equanimity; ahiṁsā — nonviolence; tapaḥ — austerity; īkṣā — discrimination (between the body and the soul); vana — in the forest; okasaḥ — of one dwelling, a vānaprastha; gṛhiṇaḥ — of a householder; bhūta-rakṣā — offering shelter to all living entities; ijyā — performance of sacrifice; dvi-jasya — of a brahmacārī; ācārya — the spiritual master; sevanam — serving.
Translation: 
The main religious duties of a sannyāsī are equanimity and nonviolence, whereas for the vānaprastha austerity and philosophical understanding of the difference between the body and soul are prominent. The main duties of a householder are to give shelter to all living entities and perform sacrifices, and the brahmacārī is mainly engaged in serving the spiritual master.
Purport: 

The brahmacārī lives in the āśrama of the spiritual master and personally assists the ācārya. Householders generally are entrusted with the performance of sacrifice and Deity worship and should provide maintenance for all living entities. The vānaprastha must clearly understand the difference between body and soul in order to maintain his status of renunciation, and he should also perform austerities. The sannyāsī should fully absorb his body, mind and words in self-realization. Having thus achieved equanimity of mind, he is the best well-wisher of all living entities.