Albert Barnes Commentary Judges 6:31

"And Joash said unto all that stood against him, Will ye contend for Baal? Or will ye save him? he that will contend for him, let him be put to death whilst [it is yet] morning: if he be a god, let him contend for himself, because one hath broken down his altar." — Judges 6:31 (ASV)

From the boldness of Joash in defending his son, it is likely that the majority of the Abi-ezrites sided with him against “the men of the city,” and already felt drawn toward Gideon as their national and religious leader (Judges 6:34). Joash appears as the chief magistrate of Ophrah.

Will you plead...? Will you save? — The emphasis is upon you, as if to say, What business is it of yours?