In 737, the imperial censor Zhou Ziliang () submitted an indictment against Niu, arguing that he did not have qualifications to be chancellor, and further cited a prophecy that indicated that a person named Niu would harm the empire. Xuanzong, in anger, had Zhou caned and then exiled, and Zhou died on the way. As Zhou had been recommended by Zhang, Li Linfu used this opportunity to attack Zhang, and Zhang was exiled from the capital. Later that year the deputy chief judge of the supreme court, Xu Jiao (), submitted a flattering report to Xuanzong, pointing out that capital punishment had become almost unnecessary due to the peacefulness of his reign. Xuanzong was pleased and credited the chancellors. He thus created Li Linfu the Duke of Jin and Niu the Duke of Bin. It was also around this time that a revision of the laws, led by Li Linfu, Niu, and the officials in charge of the justice system, was completed.