That sacrifice which is offered by men without desire for fruit, and as enjoined by ordinance, with a firm faith that sacrifice is a duty, is SATTVIC or pure.

aphalākāṅkṣibhiḥ = by those devoid of desire for result; yajñaḥ = sacrifice; vidhidiṣṭaḥ = according to the direction of scripture; yaḥ = which; ijyate = is performed; yaṣṭavyaṃ = must be performed; eva = certainly; iti = thus; manaḥ = mind; samādhāya = fixing; saḥ = it; sāttvikaḥ = in the mode of goodness.;