Two types of action invalidate fasting: 1) Actions that necessitate compensatory fasting later on, and 2) actions that require an additional form of compensation together with compensatory fasting.
1. Eating and drinking: If someone eats or drinks by mistake, or forgetting that he is fasting, or if he is forced to do so, his fasting remains valid and he is not required to compensate for that in any way. Abu Hurayrah quotes the Prophet (peace be upon him) as saying: “He who forgets on a day of fasting and eats or drinks, let him continue his fast. He has only been given food and drink by God.” (Related in all six main Hadith anthologies). This ruling is unanimously agreed by all scholars. In another statement by the Prophet: He who breaks his fast in Ramadan out of forgetfulness is not required to fast later on or to compensate in any way.” (Related by Al-Daraqutni and others). Ibn Abbas quotes the Prophet as saying: “God has forgiven my community what they do by mistake, out of forgetfulness and what they are forced to do.” (Related by Ibn Majah).
2. Vomiting: Involuntary vomiting does not require any compensation or later fasting. Abu Hurayrah quotes the Prophet as saying: “He who vomits involuntarily is not required to fast later on; but the one who deliberately causes himself to vomit must fast later on.” (Related by Ahmad, Abu Dawood and others). According to Al-Khattabi, all scholars are unanimous that this Hadith provides an indisputable rule.
3. Menstruation and postnatal discharge: These invalidate fasting even if they start one minute before sunset. Again, this is unanimously agreed by all scholars.
4. Deliberate ejaculation, whether through kissing and cuddling of one’s wife, or through masturbation. If ejaculation happens as a result of merely looking at a woman or day-dreaming, it does not invalidate fasting. It is considered in these cases in the same light as ejaculation during sleep.
5. Eating something that is not nourishing such as swallowing a large quantity of salt is generally agreed to invalidate fasting.
6. If during a day of fasting one intends to finish his fast, his fasting is no longer valid, even though he may not have had anything to eat or drink. Intention is an essential requirement of fasting. Therefore, if it is revoked by a new intention of breaking one’s fast, the fast is no longer valid.
As has already been mentioned, all these practices invalidate fasting and require the person concerned to fast later on in compensation.
If a person eats, drinks or has sexual intercourse with his wife thinking that the sun has already set or that the starting time of fasting is not due yet, and later realizes that he was mistaken with regard to the time, he is required to compensate by fasting a day later on, according to the majority of scholars including the four main schools of Fiqh, or Islamic law. Some very distinguished scholars, however, including Ishaq, Dawood, Ibn Hazm, Ata’ and others, believe that his fast is valid and he is not required to compensate. They base their argument on the Qur’anic verse: “No liability is attached to you in what you do through a genuine mistake, but you are liable for what you do deliberately.” (33: 5)
We have already quoted the Prophet’s tradition which states that God has forgiven Muslims anything they do through genuine mistake.
It is reported that during Umar’s time, people finished their fast on an overcast day when large containers of water were brought out from Hafsah’s rooms (his daughter and the Prophet’s wife), and they all drank. Sometime later, the sun reappeared through the clouds. People were very depressed and some of them suggested that they should fast in compensation. Umar said: “Why? By God, we were not inclined to break God’s law.”
Al-Bukhari relates that Asma’ bint Abu Bakr, the Prophet’s sister-in-law, said: “One day in Ramadan during the Prophet’s lifetime, we broke our fast when it was very cloudy. Later on, the sun reappeared.” Imam Ibn Taymiyah comments that this statement proves two points: 1) That people are not required to delay ending their fast when it is cloudy until they are absolutely certain that the sun has set. The companions of the Prophet did not do that, and the Prophet did not order them to do so. We know that the Prophet’s companions were better informed about Islam and more obedient to God and His Messenger than any succeeding generation. 2) That such a mistake does not require compensation by fasting later on. The Prophet did not order his companions to fast later. Had he done so, we would have been told. Since we are not told of that, we conclude that he did not order them to fast later.
Fasting and Compensation Together
Both fasting later and compensation are required if a person has sexual intercourse with his wife during a day of fasting. Abu Hurayrah reports: “A man said to the Prophet: ‘Messenger of God! I am doomed.’ The Prophet asked: ‘On what grounds have you been doomed?’ He said: ‘I had sexual intercourse with my wife in Ramadan.’ The Prophet asked the man: ‘Can you afford to free a slave?’ The man answered in the negative. The Prophet asked him: ‘Are you able to fast two consecutive months without interruption?’ The man again answered in the negative. The Prophet then asked him: ‘Can you afford to feed 60 people?’ The man again said no and sat down. Some time later, the Prophet was given a large container full of dates. He gave it to the man and said: ‘Give this for charity.’ The man said: ‘To any people who are poorer than us? There is no family in Madinah which more badly needs these dates than we?’ The Prophet laughed so much that his back teeth were visible. He said to the man: ‘Take it to your own family.’ (Related in all six anthologies).
Most scholars agree that both the man and the woman are required to give this sort of compensation since they both have intercourse deliberately out of their own free will, during a day of Ramadan on which they have intended to fast. If they have forgotten that they are fasting, or if they are forced to have intercourse, or if they have not intended to fast, then no compensation is required of either of them. If the man forces his wife to have intercourse with him, or if she was exempt from fasting, the compensation is required of him alone. Imam Al-Shafie believes that the woman is not required to give compensation at all, if she has intercourse with her husband, whether she is willing or unwilling. She is only required to fast a day later instead. Imam Ahmad ibn Hanbal is of the same opinion.
Fasting Later
If someone does not fast one day or more in Ramadan for any reason, he is required to fast later on, but this does not mean that he should fast immediately when Ramadan is over. He can choose to fast at any time which is convenient for him. The same applies to compensation. It is authentically reported that Aishah, the Prophet’s wife, used to fast in the month of Shaaban in compensation for the days she did not fast in Ramadan of the preceding year; that is over ten months later. Each day of Ramadan is compensated for by fasting one day instead. Moreover, if one did not fast on several days in Ramadan and he is fasting them later on, it is not necessary for him to fast on consecutive days. If he delays fasting in compensation for over one year, he fasts the new month of Ramadan in the normal way when it falls due, and then he fasts those compensatory days later on without incurring any additional penalty, whether this delay was for good cause or not.
This is according to the Hanafi school of Fiqh. Other schools of Fiqh agree with this verdict if the delay is for a valid reason. If not, the person concerned is still required to fast a similar number of days, but he is also required to feed a needy person for each day. This view, however, does not seem to be based on any firm grounds. The Hanafi view seems to be the weightier one in this instance.