According to the passage, why did the byzantines want belisarius to stake everything in a single battle against the goths?

"but when the corn-lands had no more grain and all the romans (byzantines) had come into an exceedingly evil plight, they surrounded belisarius and tried to compel him to stake everything on a single battle with the enemy (goths), promising that not one of the romans (byzantines) would be absent from the engagement."
—history of the wars, book vi, article iii