A.T. Robertson Commentary Acts 23:9

"And there arose a great clamor: and some of the scribes of the Pharisees part stood up, and strove, saying, We find no evil in this man: and what if a spirit hath spoken to him, or an angel?" — Acts 23:9 (ASV)

Strove (διεμαχοντο). Imperfect middle of διαμαχομα, old Attic verb, to fight it out (between, back and forth, fiercely). Here only in the N.T. It was a lively scrap and Luke pictures it as going on. The Pharisees definitely take Paul's side.

And what if a spirit hath spoken to him or an angel? (ε δε πνευμα ελαλησεν αυτω η αγγελοσ?). This is aposiopesis, not uncommon in the N.T., as in Lu 13:9; John 6:62 (Robertson, Grammar, p. 1203). See one also in Ex 32:32.