Formerly, the deities, while tilling the earth whereon they celebrated a sacrifice, used the a god for striking the bullocks yoked to the plough. Hence, in cultivating earth for such a purpose, one may, without incurring censure or sin, apply the goad to bullocks. In other acts, however, bullocks should never be struck with the goad of the whip.
प्रचोदनं देवकृतं गवां कर्मसु वर्तताम्। पूर्वमेवाक्षरं चान्यदभिधेयं ततः परम्॥