《旧唐书·列传·卷七十八》
并设置仗马两匹，需要骑马就去，天下治理得好，正是因为采用了这些措施。
并置立仗马二匹，须有乘骑便往，所以平治天下，正用此道也。
And he set up two horses for guards, and whenever he needs to ride a horse he shall do so, the reason for the country being governed well is precisely because these measures were adopted.