E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
(Latin, coms-stabuli) means Master of the Horse. The constable of England and France was at one time a military officer of state, next in rank to the crown.
To overrun or outrun the constable. To get into debt; spend more than ones income; to talk about what you do not understand. (See below.)
Quoth Hudibras, Friend Ralph, thou hast
Outrun the constable at last;
For thou hast fallen on a new
Dispute, as senseless as untrue.
Butler: Hudibras, i. 3.
Whos to pay the constable? Who is to pay the score?
The constable arrests debtors, and, of course, represents the creditor; wherefore, to overrun the constable is to overrun your credit account. To pay the constable is to give him the money due, to prevent an arrest.