Verses 41-48 ought be read for a better understanding of the text. On the day of Judgment Jesus will find faithful and wise stewards, 42-44. He will also find those who are the very opposite and will destroy them, 45-46. There will be degrees of punishment, depending on the knowledge of the wrong-doer, 47-48.
Now comes our text which speaks of the imminent crucifixion and death of Our Lord and how the message of this will affect people. It is not a pretty picture. Human beings would like the Gospel to give us a world in which there is constant peace among men. But it will never be so. It is a grim picture which Jesus gives us.
Verses 49-50 are found only in Luke. The two verses are parallel to each other with emphatic nouns placed first. Both verses end with exclamations. The word "fire" is metaphorical and is explained in verses 51-53. It involves His suffering and death and the Gospel which brings this message to men. If Christ had never come, there would have been no fire.
The whole verse means: "Fire I have come to cast on the earth and how I wish that it were already kindled!:
Fahling: The fire of a new faith, creating burning enthusiasm among some and fierce antagonism among others, deplorable, but inevitable, and the sooner kindled, the better.
Arndt: The clashes that would be caused by the Gospel, some people rejecting, others accepting it and even its friends opposing one another in their interpretation of its meaning. Jesus, of course, does not mean to say that it is His wish that there should be dissension and strife. He is rather speaking of the actual results of His message.
The second part of verse 49 shows the anxiety of Jesus with which He views His coming death. It is similar to John 12:27 or to His prayer in Gethsemane. He shudders but He does not shrink.
Here we have a second metaphor. He is speaking of His baptism of blood, His crucifixion, and death. Look at Mark 10:38.
Arndt: This is one of the fairly numerous statements in which Jesus predicts His Passion. Whenever He thought of it, sorrow assailed Him. . . . He wishes the task would soon be accomplished.
Literally He says: "Baptism have I to be baptized with, and how I am afflicted until it is accomplished." "It is finished" is the same verb as "accomplished." He faces an ordeal. He shudders but does not shrink.
Note the parallel thoughts spoken by Jesus in Matthew 10:34-36. There we have a prohibition. Here a question.
"Peace" means the kind of peace which humans desire, the total absence of trouble. Even Christians mistakenly look for a life of complete peace at home, in the church, and elsewhere. "On earth" is another indication of this false sort of peace which people long for. Jesus is not contradicting the many passage in which He promises and gives repentant sinners the peace of God. Look at John 14:27. He assures His own of peace, but not as the world gives peace. In his conscience the believer is constantly at peace with God. But that will not make life a heaven on earth. The prospect of millennial dreams is shattered here by Jesus. He answers His own question with a sharp: "Definitely not!"
Arndt: Strife would come; the Gospel would meet with bitter enmity.
Jesus preached Law to show man his sinfulness. Read John 15:22-25. If the Word had not been preached, the world would have gone on undisturbed. But the preaching of the Word causes divisions, not because of God or because of the Word, but because of the utter sinfulness of man.
This is an explanation. Verses 52-53 explain what Jesus means by division or dissension. By the way the word "divided against" occurs often, making the idea quite prominent.
"There shall from now on be five in one house divided." He is not saying on which side the two or the three are. The emphasis is on the word "divided against."
The picture is of a family of five: father, mother, daughter, son, and son's wife. The mother and the mother-in-law are the same person. The bride of son's wife has come to live with the family. The point is division. Jesus does not indicate whether the two or the three are on His side. Nor is He saying that the younger generation is against the older generation. And what is typical in the family is found everywhere. Look at Luke 2:34 and 2 Corinthians 2:15f.
Some acknowledge the Gospel as true, others not. On Calvary the cross in the middle divided the believing from the unbelieving wrong doer. The Gospel is a "scandal," a hateful thing, to the unbeliever. How true is not the observation in Acts 14:22. Follow Paul on his missionary journeys. Almost everywhere he went, his enemies stirred up trouble, blaming everything on Paul and the Gospel. Division, division, division!
Arndt: Even the Gospel's friends oppose one another in their interpretation of its meaning.
How true! I am not always right and there are time when I hate someone simply because he does not agree with me but later I see that he was right. I must beseech God's mercy and repent.
Luther: When Christ foresaw in the spirit that a great disturbance and revolution in the world would follow His preaching, He comforted Himself this way: 'I came to cast fire upon the earth; and would that it were already kindled!' Thus we see today that because of the persecution and blasphemy of our opponents and the contempt and ingratitude of the world many evils follow upon the preaching of the Gospel. This bothers us so much that we often think, according to the flesh, that it would have been better if the teaching of godliness had never been circulated and peace had been preserved than that the public peace would be disturbed as it has been since it was made public. But according to the Spirit, we courageously declare with Christ: 'I came to cast fire upon the earth; and would that it were already kindled!' Once this fire has been kindled, great upheavals immediately arise. For it is not some king of emperor but the god of this world, 2 Corinthians 4:4, who is provoked; and he is a powerful spirit and the lord of the whole world.
Our only protection midst all this sin and division in the world is a Word of Jesus, such as John 16:33: "These things I have spoken to you so that in My you might have peace. In the world you have tribulation but be of good courage, I have overcome the world.