Luke 10:18

ἐθεώρουν : their report was no news to Jesus. While they were working He saw Satan falling. There has been much discussion as to what is meant by this fall, and why it is referred to. It has been identified with the fall of the angels at the beginning of the world, with the Incarnation, with the temptation of Jesus, in both of which Satan sustained defeat. The Fathers adopted the first of these alternatives, and found the motive of the reference in a desire to warn the disciples. The devil fell through pride; take care you fall not from the same cause (Luke 10:20). ὡς ἀστραπὴν, like lightning; the precise point of the comparison has been variously conceived: momentary brightness, quick, sudden movement, inevitableness of the descent down it must come to the earth, etc. πεσόντα, aorist after the imperfect (ἐθεώρουν), fallen, a fact accomplished. Pricaeus refers to Acts 19:20 as a historical exemplification of the fall Satan's kingdom destroyed by the rapid spread of Christianity.