John Gill Commentary Judges 9:38

"Then said Zebul unto him, Where is now thy mouth, that thou saidst, Who is Abimelech, that we should serve him? is not this the people that thou hast despised? go out now, I pray, and fight with them." — Judges 9:38 (ASV)

Then said Zebul unto him
Not being able to put him off any longer, and willing to take the opportunity to upbraid him with what he had said:

where is now your mouth, [with which] you said, who is Abimelech, that
we should serve him ?
Dare you say the same you have done, and utter the contemptuous language concerning Abimelech, asking who he was, that he should be served? Here he is, speak to his face; what have become of those boasts and brags, and great swelling words, what you would do if you had the command of this city?

Is not this the people you have despised ?
as small and insignificant, bidding Abimelech increase his army, and come out and fight:

Go out, I pray you, now, and fight with them ;
and show yourself to be a man of courage, and not a mere blusterer, a man that can use his sword as well as his tongue.