BG 6.36-38
Yoga is hard to attain, methinks, by a self that is uncontrolled; but by the Self -controlled it is attainable by properly directed energy. Arjuna said: He who is unsubdued but who possesseth faith, with the mind wandering away from yoga, failing to attain perfection in yoga, what path doth he tread, O Krishna? Fallen from both, is he destroyed like a rent cloud, unsteadfast, O mighty-armed, deluded in the path of the Eternal?