Desiring the perfection (siddhi) of actions (karmāṇi), they sacrifice to the gods here; For quickly in the human world, perfection born of action (karma) occurs.
Desiring success in their actions, men sacrifice here to the gods; in the world of man success comes quickly from action.
(12) Desiring success in their (ritual) acts men worship here the gods; for swiftly in the world of men comes success engendered by the act [itself].
4.12 Longing for the fruition of actions (of their rites and duties), they worship the gods here. For, in the human world, success from action comes quickly.
4.12 Those who desire the fruits of their ritualistic acts, sacrifice to the gods here; for, success born of such acts quickly accrues in the world of men.
4.12 Those who long for success in action in this world sacrifice to the gods; because success is quickly attained by men through action.