when the imperial messenger reached Qing Prefecture to verify Cui's actions, the prisoners sentenced to death had no objections, stating to the imperial messenger that Cui judged correctly and that they deserved to die. At a later point, when Cui served as assistant minister of census, there was a time when he was reporting a number of expenditures—more than 1,000 items—to Emperor Taizong, and he recited them without having his books with him. Emperor Taizong found this odd and unbelievable, and he had the assistant head of the examination bureau of government, Du Zhenglun, fetch the books, and then had Cui re-recite his expenditures. As it turned out, Cui's oral report was correct without flaw, and Emperor Taizong was impressed. Around the same time, the imperial scholar Wang Xuandu () had written commentaries for the Confucian classics Classic of History and Classic of Odes, in which he disapproved of commentaries from the Han dynasty scholars Kong Rong and Zheng Xuan. Wang then asked for imperial approval to replace Kong's and Zheng's commentaries with his own, as the official commentaries. Emperor Taizong convened a group of scholars to debate before him, and as Wang was a capable debater, the scholars all could not refute him. As a result, the official Xu Jingzong requested that Wang's commentaries be declared official, and Li Xiaogong requested that it be made coextensive with Kong's and Zheng's commentaries. Cui, however, disapproved of Wang's commentaries, finding them to rely on unreliable interpretations, and so he wrote a submission rejecting Xu's and Li Xiaogong's suggestions. Emperor Taizong, agreeing with Cui, rejected Wang's commentaries. In 642, Cui was made an imperial attendant. At that time, the ministry of justice had submitted a proposal to increase the penalty for brothers of treasonous individuals, from removal from official posts to death. Emperor Taizong had his key officials discuss this matter, and Gao Shilian, Hou Junji, and Li Shiji were in favor of the increased penalties, while Tang Jian (), Li Daozong, and Du Chuke () were opposed. Most of the other officials favored the increased penalties, pointing out that during past dynasties, including Han, Cao Wei, and Jin dynasty, the penalty for treason was slaughter of three clans (father's clan, mother's clan, and wife's clan). Cui opposed, pointing out that in even more ancient times—times held ideal by Confucian doctrine—people were not punished for their families' misbehaviors, and the penalty for