But if an obstacle arises that would commonly be considered...

But if an obstacle arises that would commonly be considered to be a legitimate excuse, he does not have to fast that particular day, but once his legitimate excuse expires, he must resume his fasts.

In addition, someone who wants to fast for two months for the kaffārah of a fast of Ramadan must not start at a time when he knows a day on which fasting is unlawful – such as Eid al-Fitr (Shawal 1) or Eid al-Aḍḥā (Dhul-Hijjah 10) – will fall within the one month and one day period, nor must he fast at a time when he knows a day on which fasting is obligatory [such as a day that he had assigned in a vow] will fall within that period. Likewise, if…