The heart is the seat of our noblest feeling, which is love, and Our Lord wants to dwell in it. But we have to let Him come, first, by faith. Faith is an act of our intelligence but it calls to the deepest of our heart the act of another faculty: our will. We cannot really comprehend God without loving Him and cannot love Him in Truth without knowing Him. When I speak about knowing God, I mean the Supernatural knowledge of God named faith. And we can receive faith, which is a gift from God, only by bowing our reason in front of the mystery of the Divine Trinity.
It is certainly true that we can have faith without charity. This is the case when someone who, while being instructed in the mysteries of faith has fallen into a mortal sin. One single mortal is sufficient for expelling the love of God out of a soul. There might remain a certain natural love of God, but the supernatural virtue of charity is definitively absent from a soul who has committed one mortal sin and it can only be recovered by contrition which requires confession. Faith makes this person understand that he needs to confess as soon as possible. Omitting this would result in a terrible consequence if it should happen that death would come to take him in such a state. Faith tells him that dying without repentance would put him directly in Hell and that Hell is not a dark concept from the Middle-Age but a reality still taught today by the Church. Faith also teaches that, in order to have a true contrition, it is necessary to have a certain love of God even though this love would be still imperfect. At least, it would not be useless. But for sure, having faith without an ounce of charity would be useless.
This is the reason why Saint Paul desires that Our Lord dwell in our hearts by faith. Then he adds: being rooted and founded in charity, You may be able to comprehend, with all the saints, what is the breadth and length and height and depth, To know also the charity of Christ, which surpasses all knowledge: that you may be filled unto all the fullness of God.
In other words, if we want to grasp the measure of Divine Love, we must love too. I think that love can be understood only by love itself. Without it, our faith would be dry, mean, narrow and inhumane. It would be a Pharisaic faith nourished by an impudent pride instead of a loving faith established upon humility. Our Lord Jesus Christ has often denounced such faith. One day Jesus comes to the house of one of them and it is on the Sabbath day. The Pharisees watch Him. What a golden opportunity for them! Will he perform one of his miracles today? And they probably hope that He will, so that they can take Him and judge Him. But Jesus knows their thoughts. Is it lawful to heal on the Sabbath day?
Dear Brethren, let us not allow our faith to shrivel up because of a lack of charity but let us rather be purified by the fire of a loving heart. The Pharisees did not understand the law and neither do we if we do not love. The letters kills but the Spirit gives life! It is not the materiality of the accomplishment of the acts required by the law that saves, but the love that we put in our acts.
Jesus wants to dwell in our hearts. But first, He has to purify them. It is sorrowful, and we had a perfect example of this yesterday with the feast of the seven sorrows of Our Lady. Her heart was mystically pierced as the Heart of her Son was physically pierced. Jesus wants to dwell in our hearts but He has to pierce them in order to be in our hearts. So, let us ask our Blessed Mother to accept this work of purification. Then, our hearts will dilate and we will truly understand the full measure of the Divine Love and be filled unto all the fullness of God.