Bodily discipline is essential in order to make the ground of the heart fit to receive the spiritual seeds and bear spiritual fruit. To abandon or neglect it is to render the ground unfit for sowing and bearing fruit. Excess in this direction and putting one’s trust in it is just as harmful, or even more so, than neglect of it. Neglect of bodily discipline makes men like animals who give free rein and scope to their bodily passions; but excess makes men like devils and fosters the tendency to pride and the recurrence of other passions of the soul.
Those who relinquish bodily discipline become subject to gluttony, lust and anger in its cruder forms. Those who practice immoderate bodily discipline, use it indiscreetly, or put all their trust in it, seeing in it their merit and worth in God’s sight, fall into vainglory, self-opinion, presumption, pride, hardness and obduracy, contempt of their neighbors, detraction and condemnation of others, rancor, resentment, hate, blasphemy, schism, heresy, self-deception, and diabolic delusion.
~Ignatius Brianchaninov
Prayerful Life 