The reply is:

This is disputed among both the early and later scholars. Those who distinguish between someone who forgets and someone who acts under a mistaken assumption say that the latter can guard against his mistake, unlike forgetfulness. They draw an analogy with someone who does not fast on the day when the beginning of Ramadan is uncertain, only to discover that it was part of Ramadan. Some of the early scholars reportedly held that the fast must be made up in the case involving sunset, but not in the case involving dawn, just as when the uncertainty persists.

Those who hold that the fast is not invalidated in any of these cases say: “Our evidence is stronger, and the Quran and Sunnah support our position more clearly.” For Allah says:

“Our Lord, do not take us to task if we forget or make a mistake.”

Thus, He mentions forgetfulness and error together. Moreover, someone who mistakenly commits acts prohibited during pilgrimage or prayer is like someone who commits them forgetfully. It is established in the Sahīh that people broke their fast during the Prophet’s lifetime, may Allah bless him and grant him peace, and then the sun reappeared. The hadith does not mention that they were ordered to make up the fast. Hishām ibn ʿUrwah, however, said: “It must be made up.” His father, who was more knowledgeable than he was, used to say: “They do not have to make it up.”

It is also established in the two Sahīh collections that a group of the Companions

“used to eat until one of them could distinguish a white thread from a black thread. The Prophet, may Allah bless him and grant him peace, said to one of them: ‘Your pillow must indeed be wide! What is meant is the whiteness of day and the darkness of night.’”

It is not reported that he ordered them to make up their fasts. They were ignorant of the ruling and were therefore acting in error.

It is established that ʿUmar ibn al-Khattāb broke his fast, after which it became apparent that it was still daytime. He said: “We will not make it up, for we did not intend any sin.” It is also reported that he said: “We will make it up”; but