Reference for Ketubot 99:1

ועשיתינהו לזניה אי אמרת בשלמא לאו דינא משום הכי עשיינהו אלא אי אמרת דינא עשיינהו בעי

and I forced them to maintain him. Now if you say that this was not [in accordance with the strict] law one can well understand why he had to force them, but if you say this is the law, why did he have to force them?

Jastrow