I will even affirm, that, in any other way, it is next to an impossibility ever to acquire a perfect mortification of the senses and passions.
The reason is obvious; the soul gives vigour and energy to the senses, and the senses raise and stimulate the passions: a dead body has neither sensations nor passions, because its connection with the soul is dissolved.
All endeavours merely to rectify the exterior, impel the soul yet farther outward into that about which it is so warmly and zealously engaged. It is in these matters that its powers are diffused and scattered abroad: for its application being immediately directed to austerities, and other externals, it thus invigorates those very senses it is aiming to subdue. For the senses have no other spring from whence to derive their vigour, than the application of the soul to themselves; the degree of their life and activity is proportioned to the degree of attention which the soul bestows upon them; and this life of the senses stirs up and provokes the passions, instead of suppressing or subduing them: austerities may, indeed, enfeeble the body, but, for the reasons just mentioned, can never take off the keenness of the senses, or lessen their activity.
The only method to effect this is inward recollection; by which the soul is turned wholly and altogether inward, to possess a Present God. If the soul directs all its vigour and energy towards this centre of its being, the simple act separates and withdraws it from the senses; the exercising all its powers internally leaves them faint and impotent; and the nearer it draws to God the farther is it separated from the senses, and the less are the passions influenced by them.
Hence it is, that those, in whom the attractions of grace are very powerful, find the outward man altogether weak and feeble, and even liable to faintings. I do not mean by this to discourage mortification; for it should ever accompany prayer, according to the strength and state of the person, or as obedience will allow. But I say that mortification should not be our principal exercise; nor should we prescribe ourselves such and such austerities, but follow simply and merely the internal attractions of grace; and being possessed and occupied with the Divine Presence (without thinking particularly on mortification) God will enable us to perform every species of it; and most assuredly He will give no relaxation to those who abide faithful in their abandonment to Him, until He has mortified in them everything that remains to be mortified.
We have only then to continue steadfast in the utmost attention to God, and all things will be rightly performed. All are not capable of outward austerities, but all are capable of this. In the mortification of the eye and ear, which continually supply the busy imagination with new objects, there is little danger of falling into excess: but God will teach us this also, and we have only to follow where His Spirit guides.
The soul has a double advantage by proceeding thus, for, in withdrawing from outward objects, it draws the nearer to God; and in approaching Him, besides the secret sustaining and preserving power and virtue received, it is the farther removed from sin, the nearer the approach is made; so that conversion becomes habitual.