Usually the word "god" would be considered a false god unless it had the large "G" in God that refers to the one true God. Here, Jesus quotes a scripture where God calls his followers gods because he has chosen them to represent Him on earth.
Jesus asks this question in order to point out information the Jewish religious leaders should already know. "It is written." (See:[[rc://en/ta/man/translate/figs-litotes]]) (See: [[rc://en/ta/man/translate/figs-rquestion]])
This phrase gives the picture of Scripture being something that controls us and that control cannot be broken or made loose so that we could escape from what it says is true. Alternate translation: "nothing that is in Scripture can be shown to be false"(UDB) or "Scripture is the truth" (See: [[rc://en/ta/man/translate/figs-litotes]])