Praised be Jesus and Mary, now and forever.
Every 17th of September, Franciscans commemorate the Stigmata of St. Francis of Assisi because it's around this time of year that he received the Stigmata from our Lord in the year 1224, two years before he died. So this year is actually the 800th anniversary of St. Francis receiving the Stigmata.
St. Francis was moved to pray for conformity to Christ his whole life. That was his greatest desire, to be made like Christ. He prayed for this conformity, and he received it in a special way. He received the Stigmata, and obviously that is conformity to Christ in visible fashion, extraordinary fashion, unique fashion. It doesn't ordinarily happen. It's not part of the spiritual life; it's not part of the path to holiness to receive the Stigmata, so it's unique. But it nevertheless expresses his great conformity to our Lord.
When he received that conformity, he literally had holes, bleeding holes, in his hands, his feet, and his side, and they would hurt. When he used his hands, the Stigmata would hurt. When he walked, the Stigmata hurt. And when they changed the bandages on his side, because the wounds kept bleeding and bleeding and bleeding, it hurt. It all hurt. The Stigmata were painful. 
Maybe sometimes we imagine the Stigmata or the sufferings of the saints as being actually fun and pleasant. No, the pain that you would feel if you had a hole in your hands that bled day and night—that's the pain St. Francis felt. So, he prayed for conformity, and he received this conformity. It hurt, and even though it hurt, he still wanted it. 
That's really the key thought, the key concept I wanted to share this morning: He prayed for conformity, he received it, and even though it hurt—a lot—he still wanted it. When he felt literally in his hands, feet, and side what it was like to be crucified, St. Francis still wanted that.
And that's what it means for us to fill up what is lacking in the sufferings of Christ. There's that passage in St. Paul. What does it mean? It means that Christ, who has a physical body and a mystical body, must suffer in His head and in the members. The members must feel the sufferings of the head. And just as the head—our Lord Himself—suffered voluntarily, He wanted to be crucified. Our Lord wanted to have His hands, side, and feet pierced and to be nailed to the cross and to suffer and die for our salvation. And as the head suffered, so must the members voluntarily suffer, receiving whatever the sufferings might be, whatever that conformity might mean for us.
For St. Francis, literally, it was the Stigmata. But whatever the conformity means for us, we too, even when it hurts, even though it hurts, we have to still want it, embrace it, make it our own, and fulfill what is lacking in the sufferings of Christ. What is lacking? That voluntary acceptance on the part of the members of the mystical body.
And we should want this conformity. Christ wants to give it to us. And it will hurt sometimes because our Lord was a suffering Savior. And even though it hurts, we should still want it, because this is real love. And if we're afraid of the pain, well, as always, turn to Our Lady at the foot of the cross. Even when conformity meant pain and suffering, Our Lady was there. We should want conformity—it'll hurt, and even though it hurts, we should still want it.
Praised be Jesus and Mary, now and forever.