For one who has conquered his mind a mind is best of friends but for one who has failed to do so a mind is the greatest enemy. dhavalvadi 4 years ago For one who has conquered his mind a mind is best of friends but for one who has failed to do so a mind is the greatest enemy. 1 1 For one who has conquered his mind a mind is best of friends but for one who has failed to do so a mind is the greatest enemy. For one who has conquered his mind a mind is best of friends but for one who has failed to do so a mind is the greatest enemy.