John Gill Commentary Acts 24:19

"who ought to have been here before thee, and to make accusation, if they had aught against me." — Acts 24:19 (ASV)

Who ought to have been here before you
For they were the only persons who saw him in the temple, and what he was doing; and who by a hideous outcry raised a mob upon him, who took things upon hearsay from them:

and object, if they had ought against me ;
either with respect to sedition, or blasphemy, error or heresy, if they were capable of proving anything.