A.T. Robertson Commentary Acts 23:20

"And he said, The Jews have agreed to ask thee to bring down Paul tomorrow unto the council, as though thou wouldest inquire somewhat more exactly concerning him." — Acts 23:20 (ASV)

The Jews (ο Ιουδαιο). As if the whole nation was in the conspiracy and so in verse 12. The conspirators may have belonged to the Zealots, but clearly they represented the state of Jewish feeling toward Paul in Jerusalem.

Have agreed (συνεθεντο). Second aorist middle indicative of συντιθημ, old verb to join together, to agree. Already this form in Lu 22:5 which see. See also Joh 9:22; Acts 24:9.

To bring down (οπως καταγαγηις). Very words of the conspirators in verse 15 as if the young man overheard. Second aorist active subjunctive of καταγω with οπως in final clause, still used, but nothing like so common as ινα though again in verse 23 (Robertson, Grammar, p. 985).

As though thou wouldest inquire (ως μελλων πυνθανεσθα). Just as in verse 15 except that here μελλων refers to Lysias instead of to the conspirators as in verse 15. The singular is used by the youth out of deference to the authority of Lysias and so modifies a bit the scheming of the conspirators, not "absurd" as Page holds.