Adam Clarke on Luke 12:49

I am come to send fire - See this subject largely explained on Mat 10:34 (note), etc. From the connection in which these words stand, both in this place and in Matthew, it appears as if our Lord intended by the word fire, not only the consuming influence of the Roman sword, but also the influence of his own Spirit in the destruction of sin. In both these senses this fire was already kindled: as yet, however, it appeared but as a spark, but was soon to break out into an all-consuming flame.