“Do not think that I came to send peace on the earth. I came not to send peace, but a sword.”
These remarkable words appear to set at nought what has He has previously taught, and yet deliberately so, for they describe the means by which the ends will be reached. Note first the statement ‘I came'. It is a claim to uniqueness. No one else but Someone Who was unique could claim that they had come for such a purpose, for He is not talking about a local situation but a worldwide situation.
That Jesus has come to bring peace was made clear in Matthew 5:9, (although that was immediately followed by warnings of persecution - Matthew 5:10-12 - so that what is said here was inherent within it). It was then confirmed in Matthew 5:44-48. Thus He makes clear that the lack of peace will not arise as a result of the attitudes of His followers, but as a result of the reaction of others towards what they teach. Yet His point is that so reactionary are His words and teachings that that is what will inevitably happen. The world as a whole will not like them and will react against them. And that world includes their own families!
The whole of the Messianic hope for Israel was based on the expectation of a world of peace and harmony, although often preceded by a time of trouble. That peace was epitomised in the beautiful words of Isaiah 11. Not only would justice prevail among the poor and the meek (Isaiah 11:1-4; compare Matthew 5:3; Matthew 5:5), but even nature would be at harmony with itself (Isaiah 11:5-9). However even there that could only be achieved by first smiting the earth and slaying the wicked (Isaiah 11:4).
But the Jews thought that they had it all sorted. In the end the harmony and peace would be among them. It was the Gentiles who would be smitten and slain. So what Jesus is now saying conflicts with their ideas. For he is saying that the truth is that the very Jews themselves will be divided because of His words, and this will be because they themselves are unrighteous. And it is only out of the divisions which will arise as a result of that unrighteousness, and their resolution in God's way, (by salvation and judgment), that in the end peace will come. So they must recognise that as a result of His coming it must be sword first, and then peace.
We should perhaps note here that Jesus is not saying that He has come with the deliberate purpose of bringing a sword. He has come in order to bring truth. But His point is that His truth is sword and thus by bringing truth among the unrighteous He will divide them, simply because the unrighteous will react against His truth by using the sword. That is regularly unrighteous man's way of resolving a problem. So as a result the paradoxical thing will be that the very truth that was aimed at bringing peace, will initially have the very opposite effect because of man's sinfulness and rebellion.