《资治通鉴·魏纪·魏纪八》
如果他不能攻破城池，请战也无人理睬，军队就会士气低落疲劳不堪，势必将自动撤退，诸位将领的不愿径直进击，对您反而是有利的。
若攻城不拔，请战不可，师老众疲，势将自走，诸将之不径进，乃公之利也。
If he cannot break through the city, no one will pay attention to his request for battle, the army will be demoralized and exhausted, and will inevitably retreat automatically. The generals' unwillingness to attack directly is actually beneficial to you.