Grace to you and peace from God our Father, and from our Lord and Savior Jesus Christ. Amen.
Hearing the text, our Old Adam takes the words of Jesus as a set of guidelines for what we should be doing so that He will allow us into heaven. We've got to get on the ball and do more to help the poor and the needy so that we will be counted worthy to enter heaven. And so we keep looking for spiritual checklist that we can fulfill: feed the hungry–check; clothe the naked–check; visit the sick–check. There, I've done my part; I'm being a Christian now. But by doing that, you are putting your faith in yourself, not in Christ. To do that is contrary to the Word of God. Let me be clear: we should help the needy and do charitable works toward our neighbor. The Fifth Commandment requires that we help our neighbor in every bodily need. But the Commandments are God's Law, and we can’t rely on the Law to save us; the Law only brings judgment.
How, then, do we understand this aright? This is not so much about good works as it is about faith in Christ. The focus is on Him and what He has done. Notice what Jesus says: “Inasmuch as you did it to one of the least of these My brethren, you did it to Me.” Jesus isn't just talking about any old charitable deeds here, but ones done towards His brethren. So just who are the brothers of Jesus that are referred to here? St. Matthew would have us understand that these brethren are in fact the preachers of the Gospel. And the difference between the sheep and the goats is whether or not they received Jesus' brethren and believed the Gospel that these men proclaimed.
In Matthew 10 the Lord Jesus said to His apostles, “He who receives you receives Me.” The preachers who are sent with the task of preaching the Gospel—these men represent Christ. To hear them is to hear the Lord Himself, and to reject such a preacher is to reject Christ; they are called and ordained by Christ to be His representatives. When a pastor says, “I forgive you all your sins,” he is not speaking for himself, but in the stead and by the command of Christ. When he says, “This is My body,” that is not his voice, but Christ's. And the same is true of Holy Baptism. Jesus is the one giving out the gift of salvation in the water. The man Jesus uses to do these tasks is really secondary; he's covered in robes, wearing a slave collar, to show that he is a servant who represents the Lord Jesus Christ. To receive a preacher of Christ is to receive Christ Himself–not because of the merits of the pastor, who is among the greatest of sinners, but because Christ is truly present in the ministry of His Word and Sacraments for your salvation.
Our text is chiefly about those who embrace and those who reject the Gospel of Christ. It's not primarily a call to do works of mercy. It's ultimately about faith in the Gospel of Christ—and works are a consequence of that faith. This faith is brought to perfection on the Last Day, when the sheep seem blissfully unaware of the things they have done. True faith focuses not on one's own deeds, but on the deeds of Christ. “When did we do all these things? All we did was believe the Gospel!” Faith forgets itself that it may forever remember and retain Christ and His eternal gifts.
Our Lord Jesus won those gifts for you by becoming needy in your place. He was weak and hungry in the wilderness. On the cross He said, “I thirst.” He Himself took your infirmities and bore your sicknesses in His own body on the tree. He was treated like a stranger amongst His own people. He put Himself into the bondage of your sin so that He might burst the bars of your captivity by His mighty resurrection. Through Christ you are set free from death and the devil; you are released from your sins; you are cleansed and forgiven in Him. He made Himself to be the least of the brethren so that you might receive the greatest of His mercies. He showed the truest and highest charity, paying with His own blood to redeem you, so that you might live in everlasting righteousness, innocence, and blessedness.
You have heard the Word, preached to you by Christ’s faithful “brethren”—men like Pastor Welp and those who have followed him. You have received their preaching as the preaching of Christ Himself. On the Last Day, Jesus will certainly say to you who believe, “Come, you blessed of My Father, inherit the kingdom prepared for you from the foundation of the world.” It's all a gift, given to you through the merits of Christ. In the name of the Father and of the Son (+) and of the Holy Spirit. Amen.
The peace of God which passes all understanding will keep your hearts and minds in Christ Jesus always. Amen.