SB 11.17.26

agny-arkācārya-go-vipra-
 guru-vṛddha-surāñ śuciḥ
samāhita upāsīta
 sandhye dve yata-vāg japan
Synonyms: 
agni — the fire-god; arka — the sun; ācārya — the ācārya; go — the cows; vipra — the brāhmaṇas; guru — the spiritual master; vṛddha — elder respectable persons; surān — the demigods; śuciḥ — purified; samāhitaḥ — with fixed consciousness; upāsīta — he should worship; sandhye — in the junctions of time; dve — two; yata-vāk — observing silence; japan — silently chanting or murmuring the proper mantras.
Translation: 
Purified and fixed in consciousness, the brahmacārī should worship the fire-god, sun, ācārya, cows, brāhmaṇas, guru, elderly respectable persons and demigods. He should perform such worship at sunrise and sunset, without speaking but by silently chanting or murmuring the appropriate mantras.