John Lightfoot on Luke 12:49

[And what will I, if it be already kindled?] What will I, seems to be used after the manner of the schools, where What do I say? is the same with I do say this: and so What do I decree or approve? is the same with This I do decree or approve. So What will I? is the same with This I will. Thus, in these words of our Saviour, What will I, if it be already kindled, the meaning is, This I will, that it be already kindled. Now what kind of fire this was which he would have already kindled, he himself explains verse 51, and so on.