《资治通鉴·唐纪·唐纪三十四》
玄宗一行经过便桥后，杨国忠派人放火烧桥，玄宗说： 官吏百姓都在避难求生，为何要断绝他们的生路呢！ 
上过便桥，杨国忠使人焚桥。上曰： 士庶各避贼求生，奈何绝其路！ 
After Xuanzong and his group passed the Bianqiao Bridge, Yang Guozhong ordered someone to set fire to the bridge. Xuanzong said, “Officials and civilians are taking refuge and seeking survival. Why should we cut off their way of life?”