Fasting is one of the pillars of Islam. The Quran and the Sunnah have clarified all its general provisions, and the noble Companions (may Allah be pleased with them)have reported that for us. In this hadeeth, Asmaa’ bint Aboo Bakr (may Allah be pleased with them) narrated that they once broke their fast during the lifetime of the Prophet ﷺ on a cloudy day, when sunlight was blocked by the clouds, and they thought that the sun had set due to the darkness. Therefore, they ended their fast, because Muslims are commanded to break the fast immediately upon sunset. Afterward, the clouds cleared and the sun reappeared, and they realized that they had ended their fast before sunset. Hishaam ibn ‘Urwah, the narrator of the hadeeth, was asked: “Were they ordered to make up for that day?” He replied that they must have made up for it, because it is incumbent on a fasting person to complete his fast until night (sunset), and they ate during the day. Ma‘mar ibn Rasheed said in his narration: “He heard Hishaam say, ‘I do not know whether they had made up for it or not.’ He doubted whether or not they made up for that fast day. However, Muslim scholars held that if a person breaks his fast during an obligatory fasting day, thinking that the sun had set, and then came to know that it had not, it is obligatory on him to refrain from eating, drinking, and sexual activity (i.e., resume fasting) until sunset and to make up for that fast day. Another scholarly view suggested that it is not incumbent on him to make up for it. It is deduced from the hadeeth that if a Mukallaf (i.e., competent for religious duties) acts upon his own personal reasoning and arrives at a wrong conclusion, he bears no sin for that, because Muslims who are competent for religious duties are required to act upon outward realities that they believe to be most likely true as per the laws of Islam..