A.T. Robertson Commentary Revelation 12:8

"And they prevailed not, neither was their place found any more in heaven." — Revelation 12:8 (ASV)

And they prevailed not (κα ουκ ισχυσαν). Here κα equals "and yet" or "but." A few MSS. read the singular ισχυσεν like επολεμησεν, but wrongly so.

Neither was their place found any more (ουδε τοπος ευρεθη αυτων ετ). First aorist passive indicative of ευρισκω, to find. Probably αυτων is the objective genitive (place for them), just as in 20:11 αυτοις (dative, for them) is used with τοπος ουχ ευρεθη. The phrase occurs in Da 2:35 Theod. and Zec 10:10. The dragon is finally expelled from heaven (cf. Job 1:6), though to us it seems a difficult conception to think of Satan having had access to heaven.