If you have decided and made intention to fast every Monday, do you still have to remake intention every Sunday night for the fast to be valid on Monday?
Yes. In order for any fast to be valid, one must make an intention to fast from the night preceding the day of fast with the exception of Ramadan where one can make an intention during the night of the first day of the month, and that will suffice for the remainder of the month, unless one’s fast is interrupted by travel, sickness, or a woman’s menstrual cycle and the like. When one wants to fast again, one must renew the intention to fast for future days.
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