An Israeli court on Wednesday rejected a new request by Prime Minister Benjamin Netanyahu to delay testifying at his corruption trial, ruling that he must take the stand next montheven as the country is at war in Gaza and Lebanon.

The spectacle of a sitting prime minister defending himself against graft charges is likely to further polarize Israelis, and Mr. Netanyahu’s legal troubles have long split the country. His supporters claim that a liberal deep state is trying to oust him by judicial means after failing to do so at the ballot box, and his opponents have called on him to resign, with some accusing him of prolonging the fighting and the case to keep himself in power and out of jail.

Mr. Netanyahu is battling charges of bribery, fraud and breach of trust in three separate but interrelated cases being heard in parallel at the Jerusalem District Court. He has denied any wrongdoing in the cases, which center on accusations that he arranged favors for tycoons in exchange for gifts and sympathetic media coverage for himself and his family.

The trial has stretched on since 2020 as the court has made its way through a list of more than 300 witnesses.

The court ruled that Mr. Netanyahu must take the stand on Dec. 2, after having already delayed his testimony once. On Wednesday, it quickly rejected another request, filed by Mr. Netanyahu late Sunday, asking to push his testimony back by a further 10 weeks.

Mr. Netanyahu argued that he was too busy during wartime to prepare a defense, though he has long said that he can be prime minister and on trial at the same time.