Forgetfully or absentmindedly breaking fast before the due time, or mistakenly thinking that the call for the Sunset Prayer had been made are two different things. In the first case, a fasting muslim is liable for nothing, and their fasting is valid according to the majority of Muslim scholars. In the second case, one has to make up for that day of fasting according to the four schools of Islamic jurisprudence. However, the ruling maintained by the Sheikh of Islam Ibn Taimiyah, is that his fasting is also valid in the second case and that he/she is liable for nothing.

Pointing out the ruling regarding the one who forgetfully eats or drinks while fasting, the eminent Muslim scholar Sheikh Yusuf Al-Qaradawi states: It is stated in the two authentic books of Hadith (Al-Bukhari and Muslim) that Abu Hurayrah narrated that the Prophet (peace and blessings be upon him) said: “Whoever eats or drinks forgetfully should complete his fast, for what he has eaten or drunk has been granted to him by Allah.” The same hadith was reported by Ad-Daraqutni with an authentic chain of transmitters, but with a different wording as follows: “… for it is sustenance granted to him by Allah, so he is not liable to make up for it.” It is also reported by Ad-Daraqutni, Ibn Khuzaimah, Ibn Hibban and Al-Kakim with an authentic chain of transmitters and with the following different wording: “Whoever eats or drinks forgetfully while in a state of fasting in Ramadan, he is liable for neither compensation nor expiation.” The last hadith was also reported by Al-Hafiz Ibn Hajar. These hadiths clearly show that eating or drinking forgetfully does not affect the validity of one’s fasting, which conforms with the verse in which Almighty Allah says: (Our Lord! Condemn us not if we forget, or miss the mark!) (Al-Baqarah: 286), and it is stated in a hadith that Almighty Allah granted this supplication. Moreover, the Prophet (peace and blessings be upon him) said in another hadith: “Verily, Allah pardons this nation (i.e., the Muslims) for whatever they do by mistake, whatever they do out of forgetfulness and whatever they are forced to do.”

Pointing out the ruling regarding the one who absentmindedly eats or drinks while in a state of fasting, mistakenly believing that the sun has set, the eminent Muslim scholar, Sheikh Yusuf Al-Qaradawi, states:

If a Muslim eats, drinks, or has sexual intercourse while in a state of fasting, mistakenly thinking that the sun has set (or that dawn has not yet started), his fasting is deemed invalid according to the four schools of Islamic fiqh. This is because he had done what invalidates fasting, namely eating during the daytime in Ramadan. Therefore, it is obligatory for him to make up for such a day of fasting later, though he is not considered to have committed a sin.

In this regard, Ishaq ibn Rahwiyah and Dawud maintain that one’s fasting is still valid in this case, and that he is not liable for compensation. The same is narrated to have been maintained by `Ata’, `Urwah ibn Az-Zubayr, Al-Hasan Al-Basri, and Mujahid. They base their opinion on the following narration of Al-Baihaqi on the authority of Zayd ibn Wahb: “While we were sitting in the Mosque of Madinah (while fasting) during Ramadan, and it was cloudy then, we saw that the sun disappeared and it was evening. Then we were offered pots of milk from the house of Hafsah and `Umar (may Allah be pleased with them) drank (from the milk to break fasting) and so did all of us. No sooner had we done that than the clouds vanished and the sun reappeared. Thereupon, we said to each other, ‘We should make up for this day of fasting later.’ When `Umar heard of that, he said, ‘By Allah, we do not have to make up for it, and we were not inclined to commit a sin.’” (This narration has an authentic chain of transmitters, yet its authenticity was doubted by Al-Baihaqi because of its being different than the other narrations of the same incident. He said that though Zayd was a trustworthy transmitter, erring was probable. Yet, the arguments of Ibn Taimiyah support this narration of Zayd, especially that it is a clear, well-founded narration, so erring is not probable.)
Moreover, it is stated in Al-Bukhari’s authentic book of Hadith that Asma’ bint Abi Bakr narrated: “We broke our fast during the lifetime of the Prophet on a cloudy day and then the sun reappeared.”
Ibn Taimiyah, the Sheikh of Islam, maintains that the aforesaid narration indicates two things:
1. It is not desirable to delay breaking the fast on a cloudy day until the sunset is verified, for the Companions did not do so, nor did the Prophet (peace and blessings be upon him) command them to do so; the Companions are more knowledgeable and pious, and more obedient to Allah and to His Messenger than the following generations.

2. There is no compensation required in this case, for if the Prophet (peace and blessings be upon him) had ordered them to make up for that day, it would have been publicly known. They were reported to have broken their fast before the due time, so if the Prophet had commented, it would have been reported as well. This shows that the Prophet did not command them to make up for that day.

If it is argued that Hisham ibn `Urwah narrated that the Prophet (peace and blessings be upon him) ordered them to make up for that day, the reply is that Hisham said it according to his own opinion, and that such a Prophetic command is not mentioned in that hadith. Also, Hisham did not know whether the Prophet had ordered them to make up for that day or not, and this is shown in this narration of Mu`ammar, who said: “I heard Hisham saying, ‘I do not know if they made up for that day or not.’” The two cases were narrated on his authority by Al-Bukhari, and Hisham narrated the hadith in question on the authority of his mother, Fatimah bint Al-Mundhir, who reported it on the authority of Asma’. On the other hand, Hisham narrated on the authority of his father, `Urwah, that the Prophet did not order them to make up for that day, bearing in mind that `Urwah knew better than his son, Hisham. This is also the opinion of Ishaq ibn Rahwiyah, who was contemporary with Ahmad ibn Hanbal and agreed with the latter’s school of Islamic jurisprudence, whether related to the principles or the branches of Islamic jurisprudence. When Ahmad ibn Hanbal was asked about Ishaq, he used to say, showing their harmony of opinions, “Should I be asked about Ishaq or should he be asked about me?”

Furthermore, Almighty Allah says: (and eat and drink until the white thread becometh distinct to you from the black thread of the dawn) (Al-Baqarah: 187) This verse, side by side with the recurrently narrated hadiths of the Prophet in this regard, shows that a Muslim who intends fasting is commanded to eat and drink until the dawn is verified to be due. If there is doubt, he is commanded to go on eating and drinking freely.