The verses of today contain three pronouncements regarding the nature of Jesus’ mission. The first is that he has come to cast fire on the earth. Fire is used as an image of God’s judgement, but ironically when it comes on the disciples at Pentecost (Acts, 2,3), it is the purifying fire of the Holy Spirit. Nevertheless, the crisis of judgement is never far away.
The second is about his own baptism, which may be an allusion to his death or to the conflict and distress in which he would be immersed. This governs his whole life. Until he completes his mission, he will not be satisfied.
The third is about the division that his mission will cause. Although the kingdom of God is characterised by reconciliation and peace, the announcement of that kingdom is always divisive because it requires decision and commitment. Though this announcement will indeed cause stress and division, Jesus will not shy away from it because it is the Mission given to him by his Father. Anyone who commits him/herself to Jesus must also then be prepared for the opposition that they will face.
The reason why the announcement of the kingdom brings division is because it calls for a radical change of heart and mind. It overturns our value system and calls us to a life that is challenging and if lived fully also challenges others. It calls for decision and commitment at every moment.