It is instructive to note that Christ dwells only in the vital center of our being, not in the tongue, which would produce only a mouth religion, not in the hand, which would make a lifeless routine of works, but in the heart, which rules the tongue, the hands, and the feet, making them the instruments of a glad and willing service. He never takes up his abode in the brain alone; but it is his purpose, after taking possession of the heart, to extend his conquest to the head. To reverse this order would reduce Christianity to a theory instead of a joyful experience. Alas, too many have proved the truth of this declaration. A Christ flitting through the intellect now and then, gives no such repose of soul as the Christ who becomes a permanent resident of the heart, year after year, and decade after decade. The beauty of this is that he who carries him through life will have his presence in death. A good lady in a love-feast once said, "I mean to carry heaven with me through life, then I shall be sure of it at the end of my journey."
The door through which Christ comes in and takes up his abode in the heart is faith. Faith widens the soul so that more and more can be grasped. It has been said that "more depends upon taking in faith than upon giving and doing in love. For the more we take of the fullness of God, the more we can live." Faith is the inner man's vision, his reason, and his light. Such faith is possible when the heart is purified of sin. Then the eye is purged of film. The pure in heart see God. Only they have a spiritual perception which makes him real.
— Half-Hours with St. Paul and Other Bible Readings Chapter 4.