You have heard that after his sufferings and death Christ our Lord arose from the dead and entered upon, and was enthroned in, an immortal existence. Not that he might sit up there in heaven idly and find pleasure in himself, but that he might take charge of the kingdom of which the prophets and all the Scriptures have so fully spoken, and might rule as a king. Therefore, we should think of him as being present and reigning among us continually, and never think of him as sitting up there doing nothing, but rather that he from above fills and rules all things, as Paul says to the Ephesians (4:10), and especially that he is taking care of his kingdom, which is the Christian faith, and that therefore his kingdom among us here on earth must prosper. This kingdom, as we have said, is so constituted that we all must daily increase and grow in holiness, and it is not governed by any other power save the oral proclamation of the Gospel.
This proclamation is not of men, but Christ himself sent it forth, and then put it into the hearts of the apostles and their successors so that they understood it, and into their mouths so that they spoke and declared it. This is his kingdom, and so does he rule that all of his power is comprehended in and connected with the Word of God. They who hear and believe it belong to this kingdom, and the Word then becomes so mighty that it provides all that man may need and bestows all the blessings that we may desire. For it is the power of God, and it can and will save all who believe it, as St. Paul declared to the Romans (1:16). If you believe that Christ died to save you from all evil, and will hold fast to that Word, you will find it so certain and sure that no creature can overthrow it; and as no one can overthrow the Word, neither can anyone harm you who believe it. Accordingly, with the Word you will overcome sin, death, devil and hell, and you will find a refuge in the Word and attain that which is found where the Word is, namely, everlasting peace, joy and life. In short, you will be participants in all the power that is in the Word. Therefore, it is a peculiar kingdom. The Word Is present and is orally proclaimed to all the world, but its power is deeply hidden, so that none but they who believe realize that it is so effective and that it accomplishes such great things. It must be experienced and realized by the heart.
Hence, all that we preachers can do is to become the mouthpieces and instruments of Christ our Lord, through whom he proclaims the Word bodily. He sends forth the Word publicly so that all may hear it, but that the heart inwardly experiences it that is effected through faith and is wrought by Christ in secret where he perceives that it can be done according to his divine knowledge and pleasure. That is why he says: "I am the good shepherd." And what is a good shepherd? "The good shepherd," says Christ, "lays down his life for the sheep; and I lay down my life for the sheep." In this one virtue the Lord comprehends and exemplifies all others in the beautiful parable of the sheep. Sheep, you know, are most foolish and stupid animals. When we want to speak of anybody's stupidity we say, "He is a sheep." Nevertheless, it has this trait above all other animals, that it soon learns to heed its shepherd's voice and will follow no one but its shepherd, and though it cannot help and keep and heal itself, nor guard itself against the wolf, but is dependent upon others, yet it always knows enough to keep close to its shepherd and look to him for help.
Now, Christ uses this trait or nature of the animal as an illustration in explaining that he is the good shepherd. In this manner he plainly shows what his kingdom is, and wherein it consists, and would say: My kingdom is only to rule the sheep; that is poor, needy wretched men, who well see and realize that there is no other help or counsel for them.
But that we may make it the plainer, and may understand it the better, we will cite a passage from the prophet Ezekiel, where he speaks of the wicked shepherds that are against Christ, when he says: "Should not the Shepherds feed the sheep? You eat the fat, and you clothe you with the wool, you kill the fatlings; but you feed not the sheep. The diseased have you not strengthened, neither have you healed that which was sick, neither have you bound up that which was broken, neither have you brought back that which was driven away, neither have you sought that which was lost; but with force and with rigor have you ruled over them. And they were scattered, because there was no shepherd; and they become food to all the beasts of the field and were scattered. My sheep wandered through all the mountains, and upon every high hill: my sheep were scattered upon all the face of the earth; and there was none that did search or seek after them," and so forth.
Accordingly, God reproves the shepherds who do not keep the sheep. And now mark well what he has written. His earnest intent in this paragraph is that the weak, sick, broken, those who are driven away and the lost, are to be strengthened, bound up, healed, and sought again, and that they are not to be torn to pieces and scattered. This you should have done, says he to the shepherds, but you have not done it; therefore, I will do it myself. As he says further on: "I will seek that which was lost, I will bring back that which was driven away, and will bind up that which was broken, and will strengthen that which was sick."
Here you see that Christ's kingdom is to be concerned about the weak, the sick, and the broken, that he may help them. That is, indeed, a comforting declaration. The only trouble is that we do not realize our needs and infirmities. If we realized them, we would soon flee to him. But how did those shepherds act? They ruled with rigor, and applied God's Law with great severity; and, moreover, they added their own commandments, as they still do, and when these were not fulfilled, they raved and condemned, so that they were driving and driving and exhorting and exacting, continually. That is no proper way to tend and keep souls, says Christ. He is no such shepherd as that; for no one is benefited, but is rather wholly undone,
Therefore, even though we are weak and sick, we must not despair and say we are not in the kingdom of Christ. But the more we realize our sickness, all the more should we turn to him; for that is what he is here for, to heal and make us whole. Accordingly, if you are sick and a sinner, and realize your condition, you have all the more reason to go to him and say: Dear Lord, I come just because I am a sinner; that you may help me, and make me good. Thus, necessity drives you to him; for the greater your ailment, the more imperative it is that you seek relief. And that is what he wants; therefore, he tenderly bids us to be of good cheer, and to come unto him.