Luke 12:49 - Ellicott's Commentary On The Whole Bible

I am come to send fire on the earth. — There is a strange unique abruptness in the utterance. We are compelled to assume a pause, a moment’s thought, as in one whose gaze looks out into the future, and who at once feels its terrors and yet accepts them. The fire which He came to send is the fire of judgment which shall burn up the chaff (see Note on Matthew 3:12), the baptism of fire which shall purify and cleanse as well as destroy. The Son of Man knew that this, with all its terrors, was what He came to work. If the fire was already kindled, if judgment was already passed upon the unfaithful stewards and the servants who knew their Lord’s will and did it not, why should He wish to check it? What other wish or will was right for Him than that it should complete what it had begun, even though it brought not peace, but a sword — not union, but division?