四分律比丘戒本 1.p120

1.p120

If a monk be asked to receive such things as are allowed during time of sickness, extending over a period of four months, he may accept the invitation for this period, even though he be at the time in good health, but if he exceeds such a term, except there be a perpetual invitation, or a new invitation, or a partial invitation, or a general invitation, it is pācittiya.