1 Your faith, dearly beloved, is not ignorant, and I know that you have so learned by the teaching of that Master from heaven, in whom you have placed your hope, that our Lord Jesus Christ, who has now suffered for us and risen again, is the Head of the Church, and the Church is His Body, and that in His Body the unity of the members and the bond of charity is, as it were, its sound health. But whosoever grows cold in charity, has become enfeebled in the Body of Christ.
But He who has already exalted our Head, is able also to make even the feeble members whole; provided, that is, that they be not cut off by excessive impiety, but adhere to the Body until they be made whole. For whatsoever yet adheres to the body, is not beyond hope of healing; whereas that which has been cut off, can neither be in process of curing, nor be healed. Since then He is the Head of the Church, and the Church is His Body, Whole Christ is both the Head and the Body. He has already risen again.
We have therefore the Head in heaven. Our Head intercedes for us. Our Head without sin and without death, now propitiates God for our sins; that we too at the end rising again, and changed into heavenly glory, may follow our Head. For where the Head is, there are the rest of the members also. But while we are here, we are members; let us not despair, for we shall follow our Head.
Source: Sermons on Selected Lessons of the New Testament (New Advent)